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What Is Irritable Bowel Syndrome?

Irritable Bowel Syndrome (IBS) is one of the most common gastrointestinal disorders, affecting up to 10% of the population. However, less than half of those affected receive an official diagnosis. IBS is characterised by recurring abdominal pain, discomfort, and changes in bowel habits, making it a challenging condition to manage.

Welcome to a comprehensive page on Irritable Bowel Syndrome (IBS). Here, you’ll find everything you need to know, from symptoms and causes to testing, treatments, and the best foods for managing IBS. To make navigation easier, be sure to use the Table of Contents to quickly jump to the section you’re interested in.

For the IBS treatment page go here: Irritable Bowel Syndrome Treatments

Man in blue shirt experiencing stomach pain or discomfort.

IBS: A Widespread but Often Undiagnosed Condition

IBS is one of the leading reasons people seek medical attention for digestive problems. In my clinical experience, constipation, IBS, Candida overgrowth, psoriasis, and SIBO (small intestinal bacterial overgrowth) were among the most frequently seen health concerns.

  • IBS accounts for 30-50% of all gastroenterology referrals, making it the most common gut disorder seen by medical specialists (Everhart et al., 1991)
  • Many cases remain undiagnosed because people, particularly men, avoid discussing bowel issues or seeking medical help.
  • Women are twice as likely to have IBS as men  (Chandar 2017), though the exact reasons for this gender difference remain under investigation.

IBS may be common, but that doesn’t mean we should ignore it. Talking about digestive health openly and seeking professional guidance can make a significant difference in managing symptoms and improving quality of life.

Just How Common Is IBS?

Research over the years has provided different estimates of IBS prevalence:

  • A meta-analysis of 80 studies involving 270,000 people found the global prevalence of IBS was 11.2% (Lovell et al., 2012). A key study reported that IBS affects between 4% to 10% of the population worldwide (Oka et al., 2020)
  • In America, 10-15% of adults experience IBS symptoms, yet only 5-7% receive a diagnosis (gi.org).

IBS is not a single disease but a collection of symptoms influenced by multiple factors within the gut. The condition can significantly affect a person’s well-being, despite not causing permanent damage. Understanding its root causes is key to effective management.

Irritable Bowel Syndrome Causes

What Causes Irritable Bowel Syndrome?

The exact cause of IBS is not fully understood, but it is believed to involve a combination of gut-related imbalances and external factors. The cause of more frequent bowel movements seen in IBS has been attributed to many different factors, including physiological, psychological, as well as dietary factors.

The most commonly recognised causes include:

  • Gut Microbiome Imbalances – Disruptions in gut bacteria composition can influence IBS symptoms.
  • Increased Intestinal Permeability – Also known as “leaky gut,” this can contribute to chronic inflammation and food sensitivities.
  • Altered Gut Immune Function – IBS patients often exhibit low-grade gut inflammation.
  • Bowel Motility Issues – Some experience constipation, while others suffer from diarrhoea or alternating symptoms.
  • Heightened Visceral Sensitivity – IBS patients may have an increased gut pain response.
  • Brain-Gut Dysregulation – Stress and anxiety can significantly impact digestion and IBS symptoms.
  • Mental and Social Well-being – Psychological stressors can exacerbate IBS, making lifestyle changes crucial.

A study confirmed that IBS is a complex disorder influenced by these interconnected factors. Addressing IBS requires a comprehensive approach rather than a one-size-fits-all solution (Chey et al., 2015).

A woman, holding her stomach with a pained expression, speaks to a pharmacist in a pharmacy setting. Shelves with various medication boxes are visible in the background.

Commonly Used Drugs Linked to IBS Symptoms

Many people who take prescription drugs for conditions like high blood pressure or chronic pain often hear from their doctors:

“We can’t find anything wrong with your digestive system and don’t understand the cause of your diarrhea or constipation.”

However, through patient history analysis and comprehensive stool testing in our clinic, we found that many of these “unexplainable” symptoms were actually linked to drug-induced disease, a condition known medically as iatrogenic disease—essentially, collateral damage to the gut caused by medications.

It’s important to talk with your health-care provider and discuss any concerns, and more importantly – if you can take a break from the medicine to establish cause and effect, or change to a different drug.

Hidden Causes Found in Stool Testing

In many cases, our comprehensive stool tests revealed:

  • Candida overgrowth (various species)
  • Bacterial dysbiosis (imbalanced gut bacteria)
  • Parasitic infections, such as Giardia or Blastocystis hominis
  • Elevated inflammatory markers
  • Heightened immune responses

Many of these issues were overlooked because stool testing had not been completed previously.

Prescription Medications and Gut Damage

One of the most common underlying factors in these cases was a history of prescribed medications, particularly:

  • Non-steroidal anti-inflammatory drugs (NSAIDs)
  • Acid-blocking drugs (PPIs for heartburn)
  • Antibiotics

Many commonly prescribed drugs can disrupt gut flora, leading to Candida overgrowth, bacterial imbalances (SIBO), and inflammation, all of which are linked to IBS symptoms.

For greater detail about common drugs that affect the bowel click on the accordion box below:

Studies show that many pharmaceutical drugs can damage the gut lining and trigger IBS-like symptoms. Unfortunately, this remains under-recognised in conventional medicine (Philpott et al., 2014).

Drugs Linked to Constipation

  • Opiates (for pain relief)
  • Anticholinergics (for cramps or spasms)
  • Iron supplements (for anaemia, low-iron)
  • Antipsychotics (especially newer agents like clozapine)
  • Verapamil (a calcium channel blocker)
  • Frusemide (a diuretic)
  • Levothyroxine (thyroid medication)
  • Cholestyramine (used for high cholesterol)

Drugs Linked to Diarrhoea

  • Metformin (diabetes medication)
  • Iron supplements (for anaemia, low-iron)
  • Fibrates (cholesterol-lowering drugs)
  • Antibiotics (especially amoxicillin)
  • ACE inhibitors (blood pressure medications)
  • Beta-blockers (blood pressure)
  • Angiotensin-2 antagonists (blood pressure)
  • Lithium (mood stabiliser)
  • Carbamazepine (used for seizures and nerve pain)
  • NSAIDs (e.g., ibuprofen, naproxen)
  • Frusemide (diuretic)
  • 5-ASA (used for inflammatory bowel disease)
  • Proton Pump Inhibitors (PPIs) (e.g., omeprazole, pantoprazole)

Understanding the impact of medications on gut health is essential. If you suspect your IBS symptoms are linked to prescription drugs, it’s worth discussing alternative options with your healthcare provider or looking into gut-healing strategies to counteract the effects of these medications

Take-Away

IBS is a complex, widespread condition that affects millions of people worldwide. Despite its prevalence, many remain undiagnosed due to the stigma surrounding digestive issues. Addressing IBS effectively requires understanding its many potential causes, including medications, and making dietary and lifestyle changes, and seeking the right support.

In the following sections, let’s explore the latest research on IBS, effective treatment strategies, and practical steps you can take to regain control over your gut health.

Bowel Disease Prevalence In USA

(Sperber et al., 2021)

  • Irritable bowel syndrome (IBS) is at 4.8% to 5.3% of the population
  • Celiac disease is at 0.7% of the population
  • Inflammatory bowel disease (IBD) is at 0.5% of the population

Diarrhea, Constipation, or Both?

IBS presents differently in each individual, but most people fall into one of the following patterns:

  • IBS-D (Diarrhoea-predominant IBS)
  • Frequent, loose stools and a sudden, urgent need to use the toilet.
  • IBS-C (Constipation-predominant IBS)
  • Hard stools, difficulty passing bowel movements, and a feeling of incomplete evacuation.
  • IBS-M (Mixed-type IBS)
  • Alternating between diarrhoea and constipation, sometimes unpredictably.

For greater detail about the sub-types click on the accordion box below:

The 4 IBS Sub-Types

Did you know there are four predominant IBS subtypes? The different subtypes of IBS are identified according to the shape and consistence of stools, referring to the Bristol Stool Scale (BSS) (Chey et al., 2015) Please refer to the BSS image on this page)

  • 1. IBS-C – is identified by abdominal pain and discomfort, along with constipation symptoms such as infrequent bowel movements and difficulty passing stools. With IBS-C, more than 25% of bowel movements are classified as level 1 or 2, and less than 25% as level 6 or 7 on the Bristol Stool Scale.
  • 2. – IBS-D – is characterised by abdominal pain/discomfort and frequent, urgent diarrhoea. With IBS-D, more than 25% of bowel movements are classified as level 6 or 7, and less than 25% as level 1 or 2 on the Bristol Stool Scale.
  • 3. – IBS-M – involves a mix of constipation and diarrhoea symptoms, alternating between the two. With IBS-M, more than 25% are constipated (level 1 or 2) and more than 25% diarrhoea (level 6 or 7) stools.
  • 4. – IBS-U – is used when symptoms don’t align with any specific subtype or when there isn’t enough information to classify the subtype. With IBS-U, the symptoms meet other criteria for IBS, but no more than 25% of stools is abnormal.
Bristol Stool Chart showing seven types of stool, ranging from hard lumps (Type 1) to watery, entirely liquid stools (Type 7), with descriptions of each type.

The Bristol Stool Chart

The Bristol Stool Chart is a useful tool for assessing bowel health and is often referenced in IBS management.

It categorises stool into seven types, ranging from hard, lumpy stools (Type 1 and 2, common in IBS-C) to loose, watery stools (Type 6 and 7, seen in IBS-D).

People with IBS-M may fluctuate between these extremes. Tracking stool consistency using this chart can help identify patterns and guide dietary and lifestyle adjustments for better IBS symptom control. Download your own copy of the Bristol Stool Chart, along with your own personal poop diary [Here].

Irritable Bowel Syndrome Symptoms

Person in a yellow sweater and jeans with a graphical insert showing bacteria, implying a focus on gut health or microbiology.

What Does Irritable Bowel Syndrome Feel Like?

Most people, at some point in their lives, will experience gastrointestinal discomfort, such as:

  • Abdominal pain or cramping
  • Bloating relieved by passing gas
  • Sudden urgency to use the toilet
  • Difficulty passing a bowel movement
  • Loose or irregular bowel motions

These occasional digestive changes are perfectly normal

Factors like diet, lifestyle shifts, and stress can temporarily disrupt digestion, but in most cases, these symptoms are mild and short-lived.

How IBS Feels Different

People with irritable bowel syndrome, however, experience gut discomfort more frequently, may experience stronger symptoms, or for prolonged periods of time. Their symptoms tend to be persistent, recurring, and often disruptive to daily life.

Most Common IBS symptoms include:

  • Cramping or sharp abdominal pain – Often relieved by passing gas or a bowel movement.
  • Bloating and a feeling of fullness – Some describe it as a “pressure” in the abdomen.
  • Changes in bowel habits – Either increased urgency, constipation, or alternating diarrhea and constipation.
  • Irregular stool consistency – Stools may be hard, lumpy, loose, or watery, varying from day to day.

Symptom Severity and Fluctuations

IBS symptoms vary greatly from person to person. Some experience mild discomfort, while others suffer from severe, daily episodes. Symptoms can also fluctuate over time, often triggered by:

  • Dietary choices
  • Emotional stress
  • Hormonal changes
  • Gut infections or illness

Understanding your unique symptom patterns and triggers is essential for managing IBS effectively. As we’ll explore further, IBS is influenced by multiple factors, and addressing both diet and lifestyle can make a significant difference in symptom control.

Irritable Bowel Syndrome Symptoms

Symptoms of IBS can vary widely among individuals, and in our clinical experience may include symptoms that are commonly overlooked such as urgency and frequency of stool, as well as feelings of anxiety or depression.

Symptoms that support IBS diagnosis  (Kellow 2001)

  • Abnormal Stool Frequency
  • For research purposes may be defined as more than three bowel movements per day, and less than three bowel movements per week.
  • Abnormal Stool Form
  • Lumpy/hard or watery/mushy)
  • Abnormal Stool Passage
  • Straining, urgency or feeling of incomplete evacuation.
  • Passage of Mucus
  • Bloating or Feeling or Abdominal Distension
  • Abdominal pain

Let’s now explore some of the key IBS symptoms a little further:

Abdominal Pain

A large population-based study of over 1,800 IBS patients found that those with IBS-C (constipation-dominant) experience more frequent and bothersome abdominal pain than those with IBS-D (diarrhea-dominant) (Shah et al., 2020). While diet alone may not completely alleviate abdominal pain, research suggests that adopting a healthier lifestyle and dietary habits can significantly improve quality of life for IBS sufferers (Di Rosa et al., 2023).

Stress is also a major trigger for IBS-related abdominal pain. A real-time symptom tracking study found that higher stress levels correlate with increased pain scores in IBS patients. This research highlights the importance of addressing daily life stressors when managing IBS symptoms (Vork et al., 2020).

Bloating

Bloating is one of the most common gut symptoms I’ve encountered in clinical practice. I’ve lost count of how many times I’ve heard patients say, “I need to loosen my waistband after a meal.” Sometimes, bloating can be linked to something as simple as poor chewing habits. Chewing affects digestion, and poor chewing can lead to poor pooping—I know this because I spent decades talking to patients about exactly that.

Research supports just how prevalent bloating is among IBS sufferers. In one study, 60% of IBS patients reported bloating as their most troublesome symptom, while 29% found abdominal pain to be the most bothersome (Lembo et al., 1999). Another study found that up to 90% of IBS patients experience bloating (Chang et al., 2001).

Women with IBS seem to experience bloating and abdominal distention more frequently than men, particularly before their menstrual cycle (Lee et al., 2001). Stress is another factor—research suggests that stress worsens bloating in IBS, while relaxation techniques may help relieve it (Hasler 2007).

Gas

Many people experiencing gut discomfort often attribute their symptoms to excess gas, believing it to be the culprit behind bloating, belching, fullness after eating, or flatulence. Before consulting a doctor or gastroenterologist, patients frequently experiment with dietary changes and over-the-counter remedies in an attempt to ease their discomfort.

Gas-related symptoms are particularly common in IBS sufferers, where bloating, abdominal distension, and flatulence are among the primary concerns. Unfortunately, these symptoms have sometimes been dismissed by medical professionals in the past. However, scientific research into intestinal gas is now gaining momentum, shedding light on a long-overlooked issue.

For many IBS patients, bloating and distension can be even more distressing than abdominal pain, significantly affecting their quality of life. Recent studies confirm both the prevalence of these symptoms in IBS and the considerable discomfort they cause (Hungin et al., 2003).

Diarrhoea

There is nothing worse than feeling uncertain about your bowel movements. I know this personally, and I’ve spoken with countless patients who have experienced the same distress. The lack of confidence in leaving the house, the embarrassment, and the disruption to daily life can be overwhelming. For some, it even affects their ability to work—one IBS patient I recall had to quit his truck-driving job because of frequent, unpredictable bouts of diarrhea.

The most common IBS subtype is diarrhea-predominant IBS (IBS-D), affecting approximately 40% of IBS patients in the United States, Canada, and England (Pallson et al., 2020).

IBS-D is diagnosed when at least 25% of bowel movements are classified as Type 6 or 7 on the Bristol Stool Scale (BSS), with less than 25% being Type 1 or 2. Studies suggest that individuals with IBS-D may have a higher prevalence of food trigger reactions (Eswaran et al., 2014).

One of the most distressing aspects of IBS-D is stool urgency, which can strike suddenly and unpredictably. Research has found that IBS-D patients consider urgency to be one of their two most bothersome symptoms (Mangel et al., 2011).

Interestingly, there may also be a connection between IBS and Candida overgrowth. One study found that Candida-associated diarrhoea can produce symptoms very similar to IBS-D (Wang et al., 2014).

Constipation

Constipation-predominant IBS (IBS-C) occurs when 25% or more of bowel movements are classified on the Bristol Stool Scale (BSS) being at type 1 or 2, and less than 25% at type 6 or 7.

At present, there is no perfect diet for managing constipation-dominant IBS. However, focusing on nutrition is the primary strategy to alleviate IBS symptoms, especially when it comes to stopping sugars, alcohol, processed foods, and other similar potential dietary triggers. I always tell patients to “cut the crap” first, that is, get rid of the obvious crappy foods. You’d be surprised how many processed foods and drinks alter our bowel function.

The low-FODMAP diet is currently the most popular choice for managing IBS, yet, its effectiveness seems to be more significant for IBS-D (diarrhoea-predominant) than IBS-C patients.

A recent study looked at both IBS-C and IBS-D and found that IBS-C patients had more methane in their breath, linked to higher levels of certain gut bacteria (Methanobrevibacter). This methane was tied to worse constipation symptoms, the higher the methane levels detected the worse the constipation scores. When methane increases it slows down gut movements, making constipation worse. (Villanueva-Millan et al., 2022)

Bowel Change Triggered By Food or Stress

Some IBS patients have what I call a “touchy” bowel—one that reacts quickly to certain foods or changes in diet. However, this sensitivity isn’t limited to food; it can also extend to stress and emotions. It’s not uncommon for an IBS patient to suddenly develop diarrhea after an emotional event—as if their gut is reacting instantly to what’s happening in their life.

Clinical research suggests that food sensitivity may play a role in IBS. Some patients experience a significant reduction in symptom severity when following elimination diets. However, the exact mechanisms behind food hypersensitivity in IBS remain unclear (Choung et al., 2006).

Mucus In Stool

Unisex toilet sign on a wall.

I’ve had patients with chronic IBS talk to me about finding mucus in their stool. Mucosal biofilms are present in 57% of patients with IBS and 34% of patients with ulcerative colitis compared with 6% of people without IBS symptoms. The presence of mucosal biofilms is a feature in a subgroup of IBS-D (diarrhoea). These biofilms have been confirmed to be dense bacterial biofilms. (Baumgartner 2021)

Anxiety and Irritability

A person in a light green shirt rubs their eyes with both hands while sitting indoors.

From experience I can tell you that many IBS patients have some level of anxiety, depression, or mood swings they are aware of. Study results revealed that people with IBS were more likely to experience moderate to severe anxiety compared to those without IBS. This high prevalence underscores the strong connection between IBS and anxiety disorders. (Alhazme et al., 2024).

Did you know that about one-third of people with IBS also deal with depression? (Staudacher et al., 2023) Both gut problems and psychological issues drive people with IBS to seek medical help, but the mental health side can have a bigger impact on long-term well-being. The best way to help is with a mix of treatments that target both the gut and the mind.

Irritable Bowel Syndrome Flare-Up Symptoms

During an IBS flare-up, symptoms may intensify and become more pronounced. Symptoms may include:

  • Increased severity of abdominal pain or discomfort
  • More frequent bowel movements
  • Worsening bloating and gas
  • Increased sensitivity to certain foods or stressors.

Some people find that during a flare-up, they react more strongly to specific foods than usual. The duration and severity of flare-ups can vary significantly, making it essential to identify individual triggers.

Stress is a well-known trigger for IBS flare-ups. In our clinic, I often saw patients experience worsened symptoms when treatments were initiated, adjusted, or discontinued. Other common IBS triggers include overexertion, emotional stress, infections, and poor sleep

Female medical professional with a stethoscope against a white background.

When To See Your Medical Doctor

In our naturopathic clinic, we always worked alongside general practitioners (GPs), particularly seeking those out and forming relationships with GPs trained in functional and integrative medicine. This approach allowed patients to receive the best of both worlds—combining experienced natural medicine approach and the latest in scientific advancements. While many IBS cases can be effectively managed at home, some symptoms may require medical evaluation and treatment.

You should see a medical doctor or gastroenterologist at your earliest convenience if you experience:

  • Blood in the stool or rectal bleeding
  • Unexplained or rapid weight loss
  • Sudden changes in bowel habits
  • Persistent anaemia or unexplained tiredness (possible iron deficiency)
  • Night-time gut symptoms that disrupt sleep
  • Severe abdominal pain not relieved by passing gas or stool
  • Family history of colorectal cancer
  • Family history of inflammatory bowel disease (ulcerative colitis – IBD)

While most IBS cases do not indicate serious disease, “alarm symptoms”—such as bleeding, significant weight loss, or ongoing severe pain—can be red flags for underlying organic conditions. Seeking prompt medical attention ensures accurate diagnosis and proper treatment.

For greater detail about the medical/scientific way of diagnosing IBS click on the accordion box below:

What is the Rome IV Diagnostic Criteria?

The Rome IV diagnostic criteria was introduced in 2016, representing the latest (the 4th) set of medical guidelines used in the diagnosis of irritable bowel syndrome.

To be diagnosed with IBS, a person needs to have the following symptoms:

  • Recurring abdominal pain more than once per week for at least 3 months
  • Abdominal pain with a change in bowel habits and stool frequency

To qualify for an IBS diagnosis, according to Rome IV criteria, these symptoms must have been happening for the past three months, with the first signs showing up at least six months before diagnosis. (Hinder et al., 2023)

If any of the alarm symptoms are noticed, it could signal a more serious underlying health issue, especially for patients suspected of having IBS according to Rome IV criteria. (Yang et al., 2022).

For this reason our clinic has always recommended our patients to seek qualified medical advice without delay, including a gastrointestinal medical evaluation (colonoscopy if required) for a better understanding of any underlying condition. A physical examination and reference to the Rome IV IBS criteria are important. Developed by experts in functional gastrointestinal disorders, the Rome criteria have been refined to be clinically applicable. (Lacy et al., 2017)

According to the Rome IV diagnostic criteria, irritable bowel syndrome is defined by recurrent abdominal pain and changes in stool form and/or frequency. (Mearin et al., 2016) Further IBS classification, based on Rome IV criteria, includes:

  • IBS with constipation (IBS-C; 28.5%)
  • IBS with diarrhoea (IBS-D; 35.0%)
  • Alternating diarrhoea/constipation (IBS-M; 31.0%)

Irritable Bowel Syndrome ICD10

The International Classification of Diseases, 10th Revision (ICD-10), is a system used to classify and code diseases and health conditions. The specific code for IBS in the ICD-10 is K58.

IBS Diagnostic Summary

To summarise the diagnosis of IBD, it is a functional disorder of the large intestine (colon) with no evidence of accompanying structural defect or disease. I’ve found in most cases the patient is annoyed with their gut symptoms, often one symptom in particular.

For some, gut pain is the main symptom, for others it may be bloating or constant gas and little pain. You can now see why the diagnosis can be tricky and take up to six years, because the main presenting symptoms can vary somewhat from patient to patient.

When you’ve seen several hundred IBS cases, you can spot the typical IBS patient in the clinic. Let’s take a look at the most common signs and symptoms of IBS now.

IBS can be characterised by a combination of the following signs and symptoms:

  • Abdominal pain
  • Colonic mucus production
  • Altered bowel function
  • Flatulence, gas
  • Constipation
  • Weight loss
  • Diarrhoea
  • Anxiety or depression

Common Conditions That Mimic IBS Symptoms               

The most common conditions that mimic IBS and may fool more than a few healthcare professionals, these conditions are celiac disease, inflammatory bowel diseases, food allergy, lactose intolerance, bile malabsorption issues, and SIBO.

Let’s talks about these briefly:

Assortment of gluten-free foods with grains, nuts, and flour around a "gluten free" sign on a slate board.

Celiac Disease

Over the years, we’ve seen many celiac patients in our clinic—some diagnosed and many undiagnosed. In the 1980s, it could take years for a young person to receive a celiac diagnosis.

Fortunately, with greater awareness and improved testing, diagnosis is now faster.

Celiac disease often presents with symptoms like diarrhoea, abdominal pain, and bloating, which can overlap with IBS symptoms. This is why ruling out celiac disease is essential, especially for IBS-D (diarrhoea-dominant) patients.

Research shows that 1.1% of IBS patients in the U.S. also have celiac disease (Almazar et al., 2018).

Now, imagine a busy doctor’s office—three more patients waiting outside—trying to distinguish between IBS and celiac.

Misdiagnosis Can Happen Easily.

To check for celiac disease in IBS patients, specialised blood tests are required, including:

  • Serum IgA and Tissue Transglutaminase (TTG) tests
  • Gliadin IgG antibodies (sometimes necessary for additional confirmation)

These tests aren’t always ordered initially, unless the doctor has extensive knowledge of gut conditions. If IBS symptoms persist despite dietary changes, a celiac screening should be considered.

Inflammatory Bowel Disease (IBD)

It’s easy to become confused when trying to differentiate IBS from IBD. Both conditions can cause abdominal pain, bloating, and changes in bowel habits, making diagnosis a challenge.

Research confirms that IBS and IBD symptoms often overlap, leading to potential misdiagnosis (Szałwińska et al., 2020). However, the underlying causes are very different—IBS is a functional disorder, while IBD involves chronic inflammation and potential damage to the gut lining.

To rule out IBD, doctors often test for:

  • C-reactive protein (CRP) – A blood marker of inflammation
  • Fecal calprotectin and lactoferrin – Stool markers indicating gut inflammation
A senior woman sits talking to a male doctor in a hospital room, with a nurse and another healthcare worker visible in the background.

In our clinic, we’ve seen hundreds of irritable bowel syndrome cases, and in several instances, inflammatory bowel disease (ulcerative colitis) was later diagnosed after recommending comprehensive stool testing. These specialised tests are invaluable in making an accurate diagnosis, helping to guide more effective treatment strategies.

Assorted common allergens like nuts, eggs, and fish displayed around a chalkboard sign reading "allergy.

Food Allergy

Food allergies can trigger gastrointestinal symptoms, including abdominal pain and bloating, often due to an immune response to certain food antigens like milk, soy, egg, gluten, and wheat. While food allergies affect around 2.5% of the U.S. population, reactions can vary significantly (Liu et al., 2010).

The two types of food reactions can be classified as being:

  • Immediate Reactions: Some allergies cause rapid, systemic immune responses within minutes.
  • Delayed Reactions: Others develop more slowly, with symptoms appearing over several days..

For those experiencing clear allergic reactions, such as skin rashes, it’s important to consult a healthcare professional who can organise appropriate allergy testing. However, it’s important to note that medical guidelines for managing IBS generally do not recommend routine food allergy testing unless there are consistent symptoms that strongly suggest a food allergy (Lacy et al., 2021).

Keep in mind that some food allergy tests may not be fully validated or standardised, so always check for lab certifications to ensure reliability.

Unisex toilet sign on a wall.

Lactose Intolerance

Lactose intolerance is often confused with IBS because both can trigger symptoms like diarrhea and flatulence. To confirm whether lactose intolerance is the cause, consider:

  • Eliminating lactose from your diet for one month.
  • Undergoing a breath test—consult your healthcare provider for guidance.

In some cases, people may experience both lactose intolerance (milk sugar) and a dairy allergy (milk protein) simultaneously. To figure out whether dairy is the issue:

  • Eliminate dairy from your diet for several weeks. If your gut is compromised and you consume a lot of dairy, it may be beneficial to go for a 3-month dairy-free period.
  • For those with mucus in the nose or throat or sinus issues, a 12-week dairy elimination period may be especially helpful.

Many people with IBS report finding relief from symptoms by avoiding lactose-containing foods for at least a month (Catanzaro et al., 2021).

Sucrose intolerance—similar to lactose intolerance—can also cause abdominal pain, bloating, and diarrhea, although its prevalence in IBS is uncertain.

To determine if sucrose is affecting you, consider:

  • Eliminating all sugar-containing foods for one month,
  • starting with junk food and ultra-processed foods like ice cream or any manufactured foods containing sugars. This approach may help identify triggers and improve symptoms.
Surgeons in scrubs and surgical masks operating on a patient in a brightly lit operating room.

Bile Acid Mal-Absorption (After Gallbladder Removal)

Having a cholecystectomy (gallbladder-removal) is a common operation, in fact, gallbladder disease is one of the most common procedures done in the United States with more than 1.2 million cholecystectomies performed every year. (Jones et al., 2023)

Bile Acid Mal-Absorption (BAM) often occurs after cholecystectomy), a condition that can lead to:

  • Bile acids accumulate in the intestines, disrupting the bacterial balance, and stimulating the colon to release more water, which results in loose stools.
  • Chronic diarrhoea caused by improper absorption of bile acids in the small intestine (Camilleri et al., 2020).

Many patients, particularly women, report experiencing diarrhoea shortly after gallbladder removal. Digestive enzymes can often be of help in cases of gallbladder-removal.

As a clinician, I’ve found it essential to ask the right questions:

  • “Can we discuss your diet before your gallbladder was removed?”
  • When did the diarrhoea start?”
  • “Did it begin after the gallbladder was removed?”

In addition to cholecystectomy, certain types of bowel surgery can also lead to bile acid malabsorption.

While bile-acid testing remains limited, treatment with specific pharmaceutical drugs may help identify the issue. However, this approach is not widely endorsed as a primary diagnostic tool. Careful patient history and symptom tracking are key in managing this condition.

A man in a blue shirt clutching his stomach, possibly in discomfort, against a blurred background.

SIBO

Small Intestinal Bacterial Overgrowth (SIBO) is prevalent in about 38% of IBS patients (Chen et al., 2018) and shares symptoms with IBS-D and other IBS subtypes. Symptoms often include bloating, diarrhea, and abdominal discomfort, which can overlap with other digestive conditions.

SIBO Diagnosis:

  • Breath testing with carbohydrate substrates (such as glucose or lactulose) is commonly used to diagnose SIBO, especially in patients with a history of abdominal surgery or conditions that predispose them to bacterial overgrowth (dysbiosis).
  • However, breath testing has been controversial due to standardisation issues and a high false-positive rate. In our clinic, we found many inconsistencies, leading us to stop relying on it (Rezaie et al., 2017).
  • Lactulose breath tests have been proposed as a method to differentiate between SIBO and IBS (Esposito et al., 2007)., but their reliability remains questionable.

SIBO Treatment:

  • For full information about SIBO treatment please go here.
  • The best approach to suspected SIBO is using high-quality herbal antimicrobials and probiotics instead of prescribed antibiotics. In clinical practice, if the patient responds well to antimicrobial treatment, it’s likely you’re dealing with SIBO, though Candida overgrowth cannot be ruled out and could also be a factor.

Because of the challenges with breath testing, the focus in treatment should be on clinical response and a thorough patient history to guide management.

Other Conditions That Mimic IBS

(Camilleri 2009)

  • Auto-Immune Disease – inflammatory bowel disease (ulcerative colitis, Crohns)
  • Candida overgrowth – Intestinal candidiasis
  • Colorectal (bowel) cancer
  • Dairy Intolerance – Lactose intolerance
  • Dietary Factors – such as excess tea, coffee, soda drinks, and simple sugars
  • Diverticular disease
  • Drug Abuse – Laxative abuse
  • Malabsorption syndromes – such as pancreatic insufficiency and celiac disease
  • Mechanical causes such as fecal impaction
  • Metabolic disorders such as Type 2 diabetes, and hyperthyroidism
  • Parasites – Infectious disease such as amebiasis and giardiasis
A person pouring capsules from a prescription bottle into their hand.

Irritable Bowel Syndrome and Pharmaceutical Medication

While pharmaceutical drugs are commonly prescribed to treat IBS, the effectiveness of many of these medications has been called into question. Studies show that the benefit of prescribed drugs is often minimal when compared to the placebo (sham drug) response.

Effectiveness of IBS Medications

For example, in randomised controlled clinical trials, Rifaximin, a commonly prescribed IBS drug, demonstrated therapeutic benefits in only 43% of IBS patients. In comparison, 34% of patients responded positively to a placebo, meaning the drug only improved symptoms in a small percentage of patients (Lacy et al., 2021).

This raises an important point: given the complex nature of IBS, it’s unlikely that drugs targeting a single receptor or mechanism—such as diarrhea—would provide a meaningful advantage over a placebo, especially since the placebo response in IBS can be as high as 40% or more (De Ponti 2013).

Purpose of Medications

Despite the questionable effectiveness of many drugs, medications are still prescribed to help alleviate IBS symptoms such as:

  • Abdominal pain
  • Diarrhoea
  • Constipation
  • Bloating

Common Pharmaceutical Medications for IBS

Medications for IBS are typically used to regulate bowel function and reduce discomfort. Depending on the symptoms, the following pharmaceutical options may be recommended by healthcare providers:

  • Laxatives – to improve constipation
  • Anti-spasmodics – to relieve abdominal cramping
  • Anti-diarrheal drugs – to control and reduce diarrhea
  • Antidepressants – to address mood disorders that may accompany IBS
  • Serotonin modulators – to target serotonin receptors in the gut, influencing bowel movements and sensitivity

How Serotonin Modulators Work

Serotonin modulators, which include serotonin agonists or antagonists, aim to control bowel function by altering the activity of serotonin, a neurotransmitter that regulates gut motility and sensitivity. By modifying serotonin levels, these drugs can help control how food moves through the digestive tract and ease IBS symptoms.

Take-Away

IBS medications may offer symptom relief, but their effectiveness is often minimal when compared to placebo treatments. Pharmaceutical drugs are still prescribed based on individual symptom profiles, with different medications aimed at improving constipation, abdominal cramping, diarrhoea, and mood disorders. However, the complex nature of IBS means that no single drug is likely to be universally effective.

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Are Antibiotics For IBS The Solution?

While antibiotics might seem like a solution for IBS, their use in treating IBS is highly questionable. In fact, when patients respond well to antibiotics, it’s more likely that they are dealing with dysbiosis, known today as SIBO, which requires appropriate antimicrobial treatment. Ironically, these patients often have a history of antibiotic use, which has harmed their gut microbiome over time.

The Problem with Antibiotic Trials for IBS

Most antibiotic trials focus on symptom relief to determine the effectiveness of the drug. However, they fail to address the underlying mechanisms of action, which is crucial for finding an effective treatment solution for IBS. Since IBS is a complex condition with an unclear development process, each patient’s underlying cause of symptoms is likely to be unique.

Recent research suggests that using antibiotics to treat IBS is still a crude approach with limited efficacy. According to studies, antibiotics can have unintended consequences, especially in patients with a dysregulated gut microbiome (Black et al., 2020).”My gut has Never Felt quite well since taking those antibiotics

Antibiotics Are Major Gut Microbiota Disruptors

In our clinic, we’ve seen many patients develop bacterial dysbiosis (SIBO) and Candida overgrowth after being prescribed antibiotics. Through examining countless patients’ medical histories and prescription timelines, we’ve found a strong correlation between antibiotic use and the onset of gut symptoms.

Many patients were initially diagnosed with IBS by general practitioners (GPs) who were unfamiliar with bacterial or fungal overgrowth in the gut. Probiotics were often dismissed as “unproven”, and the concept of the gut microbiome was not yet recognised (80s-90s). As a result, if a patient developed gut imbalances after antibiotic treatment, they were often labelled as an IBS patient, particularly if the antibiotics were prescribed years before the gut problems started.

Antibiotics and Their Role in The Development of IBS

It’s only recently that the link between antibiotics and IBS has been fully recognised. Studies have shown that antibiotics can cause profound changes in the gut microbiota, which significantly contributes to the development of IBS. As major disruptors of the gut microbiome, antibiotics seem to contribute to all aspects of IBS disease (Figure3). (Mamieva et al., 2022).

This research highlights the importance of understanding the long-term impact of antibiotic use on gut health. Instead of relying on antibiotics for IBS, it’s crucial to look at the underlying causes of symptoms and address gut imbalances with more targeted treatments, such as probiotics, herbal antimicrobials, or a low-FODMAP diet.

Irritable Bowel Syndrome Tests

Clinically, IBS is often a chronic and difficult-to-treat condition, leaving many patients feeling dismissed and frustrated due to the lack of effective medical interventions and testing options.Traditional medicine sometimes labels SIBO or Candida-related complex as IBS due to a so-called “lack of evidence.”

However, in our clinic, we frequently referred patients to medical doctors and gastroenterologists to rule out serious conditions like:

  • Bowel polyps
  • Strictures or prolapse
  • Diverticulitis
  • Hemorrhoids
  • Bowel cancer

In several cases, these referrals led to a firm diagnosis and the correct treatment—something that would have been missed if IBS was simply assumed.

Testing for IBS: What’s Involved?

There is no single test to diagnose IBS. Instead, healthcare providers rely on:

  • Medical history & physical examination
  • Exclusion of other gastrointestinal disorders
  • Blood tests & stool tests
  • Imaging studies (e.g., ultrasound, CT scan)
  • Endoscopic procedures (e.g., colonoscopy, sigmoidoscopy)

Why IBS Is Often Overlooked

Many doctors are overworked and face time constraints, making it easy to miss an IBS diagnosis. With funding cuts in primary healthcare, patients with chronic gut problems are often diagnosed with IBS by default after no “organic” cause is found.

Unfortunately, many of these patients are sent home with generic advice:

  • “Eat more fiber.”
  • “Exercise regularly.”

For chronic IBS sufferers, these recommendations often offer little to no relief, reinforcing the need for a more individualized and thorough approach to gut health

A black wire mesh trash bin filled with crumpled white papers and one crumpled red paper on top.

What is a Wastebasket Diagnosis?

In my years of practice, I noticed that many patients with “unexplained” gut issues often ended up with an IBS wastebasket diagnosis.

A wastebasket diagnosis (also referred to as a trashcan diagnosis) occurs when a patient clearly has symptoms indicating something is wrong, but the doctor cannot identify a specific cause or diagnosis. In these cases, the doctor may choose to label the issue as IBS to provide reassurance to an anxious patient, without a clear understanding of the underlying problem.

Why Does a Wastebasket Diagnosis Happen?

While it may seem frustrating, a wastebasket diagnosis isn’t the fault of the general practitioner (GP).

Often, this happens due to:

  • Pressure from the patient to assign a disease label.
  • The GP’s desire to reassure the patient and alleviate anxiety.
  • The GP’s inclination to facilitate treatment or a referral, especially when there’s no clear diagnosis.

Though the term “wastebasket diagnosis” may sound harsh, it’s important to note that not all doctors resort to this. However, in a brief 10-minute consultation, some doctors may write a prescription or refer the patient to a gastroenterologist.

The Compounding Issue

This issue becomes more complex when considering that many doctors (both past and present) may lack training in more functional digestive disorders such as:

This lack of “specialised” knowledge can contribute to the overuse of a general diagnosis like IBS, which may not address the true underlying cause of the patient’s symptoms.

Comorbidities of IBS: The Hidden Health Burden

IBS rarely exists in isolation—many patients suffer from other health conditions that develop slowly in the background. These co-existing conditions are called “comorbidities”, meaning they occur alongside IBS and may complicate treatment and recovery.

Why comorbidities matter in IBS:

  • When a person has multiple health issues, recovery can take longer.
  • The longer someone is unwell, the harder it becomes to maintain a healthy diet and lifestyle.
  • In severe cases, conventional medical treatments like prescription drugs or surgery may be necessary.
  • True holistic medicine should combine natural and science-based approaches, offering the best of both worlds.

Common IBS Comorbidities

Several conditions are linked with IBS, often tied to stress and the gut-brain connection (Bellini et al., 2014) :

  • Anxiety and heightened stress levels
  • Back pain and fibromyalgia
  • Chronic fatigue syndrome
  • Chronic tension headaches or migraines
  • Heartburn (GERD)
  • Multiple chemical sensitivity (MCS)
  • Post-traumatic stress disorder (PTSD)
  • Sleep disturbances and insomnia

Understanding these associations is critical in creating a personalised treatment plan that addresses both IBS and its related conditions.

IBS vs. Colon Cancer: Understanding the Differences

IBS and colon cancer are distinct conditions, yet they can share overlapping symptoms, making it crucial to differentiate between them. Let’s take a brief look at the differences between them both:

Key Differences Between IBS and Colon Cancer

FeatureIBSColon Cancer
CauseFunctional digestive disorderMalignant tumour growth
PainChronic, cramps, often relieved by bowel movementPersistent, worsening over time
Bowel HabitsAlternating diarrhoea/constipationBlood in stool, narrow stools, persistent changes
Weight LossUncommonUnexplained weight loss is a red flag
FatigueMay occur due to poor digestionCommon due to anaemia and cancer progression
Diagnostic TestsNo specific test, diagnosis by exclusionRequires colonoscopy, biopsy, and imaging

Why Proper Diagnosis is Essential

  • IBS is a functional disorder, meaning it affects how the gut works, but it does not cause structural damage.
  • Colon cancer is a life-threatening disease that requires early detection for the best outcomes.
  • If symptoms persist, worsen, or include red flags like blood in stool, unintended weight loss, or severe fatigue, immediate medical evaluation is crucial.

If in doubt, always consult a healthcare professional to rule out serious conditions and ensure the right treatment plan.

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IBS Needs Personalised Treatment

IBS Cookie-Cutter Protocols Don’t Work

Each IBS patient is unique, with different causes, triggers, and lifestyle factors, making effective treatment challenging. However, that’s the essence of naturopathy—treating the individual, not the diagnosis.

A standardised approach to IBS doesn’t make sense.

People have different diets, stress levels, jobs, genetics, and lifestyles, meaning no two cases are exactly alike.

For instance:

  • Some IBS patients need dietary changes, while others already eat well but experience chronic stress.
  • Some develop IBS from medications for other health conditions.
  • Others may have poor living conditions or emotional distress impacting their gut.

The Most Important IBS Treatment Recommendations

While every case is different, key IBS treatment strategies include:

  • Dietary modifications
  • Natural or pharmaceutical interventions
  • Stress management and relaxation techniques
  • Behavioural therapies (if needed)

A personalised treatment plan is crucial, especially for chronic IBS sufferers. Ideally, patients should work with a gut-health specialist experienced in IBS, SIBO, and Candida overgrowth. Leave cookie-cutter solutions to the Cookie Monster—IBS treatment requires a tailored approach.

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Irritable Bowel Syndrome Treatment

A global IBS survey revealed that chronic IBS patients would be willing to sacrifice 25% of their remaining life (approximately 15 years) or even accept a 1 in 1,000 risk of death if it meant guaranteed relief from their symptoms (Drossman et al., 2009).

This staggering finding underscores how deeply IBS affects quality of life. The chronic discomfort, unpredictable flare-ups, and emotional distress make it more than just a gut issue—it’s a life-altering condition.

Once serious conditions that mimic IBS have been ruled out and no organic disease is found, the key to effective IBS management lies in a comprehensive and personalized approach. Here are the four essential pillars of an effective IBS treatment plan:

1. Identify & Correct IBS Triggers

  • Determine if symptoms are linked to food intolerances, stress, or past medication use (e.g., antibiotics, NSAIDs, PPIs).
  • Common triggers include high-FODMAP foods, dairy, gluten, caffeine, and alcohol.
  • Assess gut irritants like artificial sweeteners, processed foods, and excessive fiber.
  • Emotional and psychological factors, such as stress, anxiety, and trauma, can worsen symptoms.

Goal: Pinpoint and eliminate individual triggers for symptom relief.

2. Restore Gut Microbiome Balance

  • Identify and treat bacterial, fungal, or parasitic overgrowth (e.g., SIBO, Candida).
  • Address gut dysbiosis by reducing harmful bacteria and increasing beneficial microbes.
  • Consider probiotics, prebiotics, and fermented foods to restore microbial diversity.
  • Investigate and treat biofilms, which protect harmful gut bacteria and contribute to chronic IBS symptoms.

Goal: Rebuild a healthy microbiome to support digestion and gut function.

3. Optimise Nutrition and Lifestyle

Goal: Support long-term gut health through sustainable nutrition and lifestyle choices.

4. Manage Stress & Gut-Brain Connection

  • IBS is a stress-sensitive disorder, making psychological support essential.
  • Techniques such as mindfulness, meditation, CBT (Cognitive Behavioral Therapy), gut-directed hypnotherapy, and breathing exercise can improve symptoms.
  • Address sleep disturbances, anxiety, and depression, which can worsen IBS symptoms.
  • Establish healthy routines and boundaries to reduce daily stressors.

Goal: Improve resilience to stress and strengthen gut-brain communication.

Let’s now look at each one of these four essential pillars of IBS treatment in more detail: on this page: Irritable Bowel Syndrome Treatments

We hope our comprehensive page about irritable bowel syndrome has given you insight into this all too common gut problem.

Please leave a comment – and share this page!

Eric

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Eric Bakker N.D.

Greetings! I am a naturopathic physician from New Zealand. Although I’ve retired from clinical practice since 2019, I remain passionate about helping people improve their lives. You’ll find I’m active online with a focus on natural health and wellbeing education through my Facebook page and YouTube channel, including this website.

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