Irritable Bowel Syndrome (otherwise known as IBS) is a chronic and often debilitating disorder that affects the lower gastrointestinal (GI) tract. This disorder affects both the small and the large intestines, and individuals with IBS may experience issues such as stomach pains, bloating, cramping diarrhea, altered bowel behaviors and constipation.

While IBS is often a long-term health issue, there are things that can be done to reduce symptoms and improve the quality of life for people that have been diagnosed with the disorder.

IBS is the most common gastrointestinal disorder, and it’s estimated that between 10-15%1 of the adult population in the United States suffers from IBS symptoms.

However, only 5-7% of adults have actually been diagnosed with the disorder, since only around 40% of individuals with IBS seek help from their physicians.

IBS Symptoms & Signs

The symptoms and signs of IBS may vary from person to person, as the disorder doesn’t affect everyone in exactly the same way.

In addition, the way in which people experience IBS symptoms varies from mild to severe, and the patterns of symptoms also differentiate between affected individuals.

People with IBS may experience the following symptoms:

  • Diarrhea
  • Constipation
  • Alternating between diarrhea and constipation
  • Stomach pains (typically in the lower part of the belly)
  • Sticking out of the belly
  • Cramps
  • Gassiness
  • Bloating
  • More firm or soft stools compared to usual bowel movements

Different Types of IBS

While most often IBS is talked about as a free-standing condition, in actuality this disorder describes a compilation of symptoms that affect the gastrointestinal tract.

There are several types of IBS, and it’s important to know which type you may have, as it plays a major role in determining which treatment will be most suitable for you.

IBS with Constipation (IBS-C)

IBS with constipation (IBS-C) is one of the most common types of this disorder.

The qualifying criteria for this type of IBS is that on the days that a person experiences at least one abnormal bowel movement, the stools are at minimum a quarter lumpy or hard, while less than a quarter watery or loose 2.

Individuals affected by this type of IBS experience less overall bowel movements, and at times may have to strain in order to have them. In addition, it may cause belly pain which is accompanied by bloating and gassiness.

IBS with Diarrhea (IBS-D)

People diagnosed with IBS with Diarrhea (IBS-D) experience issues that are opposite to individuals with IBS-C.

With this type of IBS, the stools of individuals during an abnormal bowel movement are more than a quarter loose or watery, and less than a quarter lumpy or hard.

Individuals with IBS-D may experience belly pain as with IBS-C, although the urges to go are more frequent.

IBS with Mixed Bowel Habits (IBS-M or IBS-A)

IBS with mixed bowel habits (also known as IBS with alternating constipation and diarrhea, IBS-A) is another type of IBS that some individuals with this disorder experience.

On days with abnormal bowel movements, people with this IBS type experience both watery and hard stools. In order to qualify IBS as IBS-M, both watery and hard stools must make up at least a quarter of the bowel movements.

Causes of IBS

The causes of the IBS aren’t clearly known, although several factors have been identified and linked to trigger symptoms of IBS.

Abnormalities in the Nervous System - Individuals with abnormalities in their nerves in their intestines may experience greater pains when the abdomen stretches from stool or gas.

This increase in sensitivity to movements in the bowel can cause the body to have stronger reactions to digestive processes that are otherwise normal, which can result in belly pain, constipation or diarrhea.

Intestinal Muscle Contractions - Intestines are lined with muscle tissues that contract and release in order to move food down the digestive tract.

In certain people, contractions may be stronger and last for longer periods of time, which can cause symptoms such as gassiness, diarrhea and bloating. In people with weaker intestinal contractions, the slower passing of food can lead to dry stools (IBS with constipation).

Severe Intestinal Infections - Individuals that experience severe episodes of diarrhea as a result of gastroenteritis (caused by a virus or bacteria) may develop IBS afterwards, which is referred to as Post-Infectious IBS 3.

Through a systematic review and meta-analysis, it has been found that the probability of individuals with gastrointestinal infections developing IBS after the infection increases six times when compared to healthy individuals 4.

In addition, the increased risk remains prevalent for a minimum 2 to 3 years post-infection.

Changes In The Microflora - Microflora refers to bacteria in the gut that is considered to be “good” and plays a significant role in healthy digestive processes.

In the case that the microflora is disturbed (typically after intestinal infections, or certain antibiotics), a state referred to as intestinal dysbiosis may occur, which can result in several gastrointestinal symptoms 5.

If IBS can be linked back to changes in the microflora, probiotics have shown to help in reducing these symptoms and restoring the bacterial balances.

Sensitivities to Food - Some people have negative digestive responses to certain foods, such as wheat, milk, fructose, sorbitol (a sugar substitute), fatty foods, alcohol, carbonated drinks, and more.

People react to foods differently, and the sensitivity to a certain food will vary from person to person. While there isn’t concrete evidence that sensitivity to food can cause IBS, it can trigger symptoms.

If you suffer from IBS, and want to investigate if a food in your diet is worsening your symptoms, you may benefit from taking a food sensitivity test.

IBS Risk Factors

Gender - Women are about twice as likely to have IBS when compared to men 6. While it’s not entirely clear what causes this disparity, clinicians speculate that the change in hormones during menstrual cycles may play a role in the higher vulnerability in women.

Family History - A family case-controlled study 7 concluded that relatives of a family member that has IBS were 2 to 3 times more likely to develop the disorder, when compared to the control group that did not have a family history of the disorder.

Medications - IBS symptoms have been linked to different types of medications, such as antidepressants, antibiotics as well as drugs containing sorbitol.

Emotional and Mental Health - People with IBS have a higher prevalence of also being affected by psychological distress.

While it’s not fully clear what comes first, evidence from clinical research shows that the prevalence of at least one mental disorder in those with IBS ranges from 40 to 60%, and has even been reported as high as 80% 8.

Behavioral therapy and stress management may help to reduce IBS symptoms in some people.

IBS Diagnosis

There isn’t a single test or examination that can with certainty diagnose IBS.

A typical starting point for doctors is to evaluate the symptoms, go through past medical history, as well as perform physical exams and tests in order to rule out other possible conditions and disorders.

Once the doctor is able to rule out other conditions, they may use an IBS diagnostic criteria (such as the Rome Criteria or Manning Criteria) to set a diagnosis. However, not all doctors use these criteria, and instead may refer to the general definition of IBS in order to determine the diagnosis.

Both of these criteria include a list of questions which the doctor asks the patient, and whether the answers satisfy the criteria will determine whether IBS can be concluded as the cause of the issues.

Manning Criteria - A threshold of two to four criteria below must be met in order to set a positive diagnosis with the Manning criteria.

  1. Onset of pain is connected to frequent bowel movements
  2. Looser stools are linked to onset of pain
  3. Pain is relieved with the passage of bowel movements
  4. Noticeable bloating of the abdomen
  5. Sensation that the evacuation is incomplete (at least 25% of the time)
  6. Diarrhea with mucus (at least 25% of the time)

Rome IV Criteria - The IV in the Rome Criteria stands for the fourth and latest update to the criteria, which was done in May 2016 by the Rome Foundation.

According to the Rome IV criteria, a patient is to be diagnosed as IBS positive if they have recurring abdominal pain at least one day per week in the past three months, with onset of symptoms at least 6 months prior, as well as experience two or more of the following:

  1. Associated to bowel movements
  2. Related to a change in frequency of stool passage
  3. Related to a change in appearance or form of stool

IBS Treatments

While most people can find a solution to reduce symptoms or to completely recover from IBS, there isn’t a single treatment that works for everyone.

Typically, treating IBS involves lifestyle and dietary changes, and for cases where IBS may be induced by stress - learning new ways to come with stress.

Common treatments for IBS include:

Dietary Management for IBS

Your doctor may recommend for you to change your diet and eating habits.

Some of the suggestions may include:

  • Eating more oat-based foods in order to help with gassiness and bloating
  • Avoiding skipping meals
  • Keeping a meal schedule to make sure that you eat that the same time each day
  • Chewing food for longer and eating slower
  • Limiting the intake of select vegetables and fruits
  • Limiting or avoiding alcohol consumption
  • Avoiding sugary and carbonated drinks
  • Drinking at minimum 6-8 cups of water during the day (avoid having it with meals)

In addition, your physician may recommend that you avoid gluten, as some people are intolerant to gluten (which can worsen IBS symptoms in those individuals).

You may also be recommended to follow a low-FODMAP diet, which is a recommended diet for the management of IBS.

Stress and Anxiety Management

In individuals where anxiety and stress are suspected to induce IBS, the following may help relieve symptoms:

  • Meditation and breathing exercises for relaxation
  • Yoga, Pilates, Tai Chi, and other physical exercises that prompt body relaxation
  • Hot showers and baths
  • Stress management counselling and cognitive-behavioral therapy (CBT)
  • Anxiety treatments with medication including SSRIs, SNRIs, or Benzodiazepines (only when recommended and prescribed by a doctor)

IBS Medications

Some medications to help reduce IBS symptoms include:

Bulk-Forming Laxatives - In people that experience IBS with constipation (IBS-C) laxatives may help to relieve constipation.

However, these medications need to be used with caution as they may have adverse effects, such as dependency, dehydration and mineral deficiencies 9.

Antispasmodic Drugs - These medications work by relaxing the intestinal muscles, which can reduce abdominal pain and cramping associated with IBS.

Antimotility Agents - Medications within this category of drugs are used to treat acute diarrhea. They work by slowing down intestinal contractions, which reduce the speed at which stool passes through the bowels.

Highly effective antimotility agents include synthetic opiates, Lomotil (diphenoxylate with atropine), as well as Imodium (loperamide) 10.

Current IBS Clinical Trials

Quick Facts About IBS

  • Irritable Bowel Syndrome (IBS) is the most common and diagnosed functional gastrointestinal (GI) disorder in the world, with prevalence rates estimated between 10-15%.
  • Among patients with IBS, the symptoms are mild in around 40% of the people, moderate in 35%, and severe in 25%.
  • Around 60% of people with IBS never seek medical attention from their physicians.
  • In the United States, there are between 2.4 to 3.5 million annual doctor visits for IBS.
  • In Asia, the distribution between men and women with IBS is fairly equal, while in the U.S, Canada, and Israel, the disorder is estimated to be twice as prevalent in women compared to men.

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Learn more about clinical studies & trials:

1 "Irritable Bowel Syndrome - American College of ...."

2 "Definition & Facts for Irritable Bowel Syndrome | NIDDK."

3 "Post-infectious irritable bowel syndrome - NCBI." 7 Aug. 2009,

4 "Systematic review and meta‐analysis: the incidence and ...." 7 Jun. 2007,

5"The Role of Gut Bacteria in IBS - Verywell Health."

6 "Sex-Gender Differences in Irritable Bowel Syndrome."

7 "Familial Aggregation of Irritable Bowel Syndrome: A Family ...." 16 Mar. 2010,

8 "Impact of psychological stress on irritable bowel ... - NCBI." 21 Oct. 2014,

9 "Laxative Abuse Treatment | Laxative Abuse Symptoms."

10 "Antimotility Agent - an overview | ScienceDirect Topics."