Scientists do not yet know exactly what causes irritable bowel syndrome (IBS). However, researchers have found that certain factors can increase a person’s risk of having IBS.

IBS causes symptoms such as bloating, stomach cramps, and changes in bowel movements. People with IBS may also have constipation or diarrhea.

A person may be able to control IBS symptoms using medication, diet, and lifestyle changes. Avoiding or reducing risk factors that may cause or exacerbate IBS may also help.

This article discusses the possible IBS causes and triggers. It also looks at treatments to help reduce IBS flare-ups.

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Doctors do not yet know what causes IBS. It is possible that various factors may cause IBS in different people.

IBS is a functional gastrointestinal (GI) disorder. These disorders involve problems with how a person’s brain-gut connection works. Scientists believe that these problems may influence if a person has IBS.

Experts also think that some conditions or events may cause a person to develop IBS. These can include:

  • some mental health conditions, such as:
    • depression
    • anxiety
    • somatic symptom disorder, where a person has high anxiety levels about their physical symptoms
  • stressful events early in a person’s life, such as physical or sexual abuse
  • small intestine bacterial overgrowth (SIBO), where the bacteria in a person’s small intestine increase or change type
  • bacterial infections in a person’s digestive tract
  • enteric infections or intestinal illnesses caused by microorganisms in contaminated food or water
  • visceral sensation, where a person has a heightened sense of pain from their internal organs
  • motility problems, where a person’s intestinal muscles contract too fast or too slow
  • food intolerances or being sensitive to some foods
  • taking antibiotics

A person with IBS may have one or more of these possible causes.

Although people with IBS may find that food intake can trigger or worsen symptoms, scientists believe true food allergies do not play a major role in IBS.

People with IBS have symptoms that may come and go over time. These periods of increased IBS symptoms are called IBS flare-ups. Various triggers may contribute to an IBS flare-up.


Doctors may recommend people with IBS avoid certain foods and drinks to minimize their symptoms. Although foods do not directly cause IBS, some may trigger flare-ups.

Examples of foods a person may avoid include:

  • spicy or fatty foods
  • foods that contain gluten, such as:
    • most cereals
    • grains
    • pasta
    • many processed foods
  • dairy products such as milk and cream
  • alcohol
  • coffee and other sources of caffeine
  • large amounts of fruit juice
  • carbonated drinks
  • foods and drinks containing sweeteners

Learn more about foods to avoid with IBS.

A doctor may recommend that a person with IBS consumes a low FODMAP diet. “FODMAPS” are carbohydrates that are harder to digest.

View the table below for examples of foods that a person may avoid or reduce their intake of when on a low FODMAP diet.

Certain fruitsapples, apricots, blackberries, cherries, mango, nectarines, pears, plums, watermelon
Certain vegetablesartichokes, asparagus, beans, cabbage, cauliflower, garlic, lentils, mushrooms, onions
Dairy productscustard, ice cream, milk, soft cheese, yogurt

A person may find it beneficial to keep a food diary and keep a record of any possible foods that may trigger or worsen their symptoms.

Learn more about the low FODMAP diet.


Feelings of stress and anxiety, or stressful events, may trigger IBS symptoms. Taking steps to alleviate stress may help to prevent a flare-up or reduce the severity of symptoms.

Learn more about IBS and stress.

No obvious trigger

In some cases, an IBS flare-up may occur without any obvious trigger.

If this is the case, a person can work with their doctor to try and identify any possible triggers and take steps to reduce the frequency or severity of flare-ups. This might include a combination of medical treatments and home remedies.

As well as dietary changes, some treatments may help reduce a person’s IBS symptoms that occur during a flare-up.

A doctor may recommend over-the-counter (OTC) treatments or prescription medication such as:

  • laxatives or fiber supplements such as psyllium for constipation
  • antidiarrheal medication such as loperamide
  • antispasmodic agents to slow contractions in a person’s bowel
  • antidepressants such as SSRIs and low doses of tricyclic antidepressants
  • coated peppermint oil capsules for abdominal pain

Various mental health therapies may also be beneficial, such as:

Other treatments a doctor may recommend include:

  • getting enough physical activity or exercise
  • probiotics
  • getting enough quality sleep

Learn more about coping with IBS.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), people assigned female at birth are twice as likely to have IBS than people assigned male at birth.

IBS is also more likely to affect people:

  • under the age of 50 years
  • who have a family member with IBS
  • with a childhood history of stressful life events
  • who have had a severe infection in their digestive tract

It is best for a person to contact their doctor for advice if they have concerns about IBS.

Here are some frequently asked questions about IBS.

What foods trigger IBS?

Foods that may trigger IBS include:

  • foods that contain gluten
  • spicy or fatty foods
  • some fruits or vegetables
  • some dairy products

IBS triggers can be different for each individual. A person may wish to consider keeping a food diary to see if they can notice any patterns of specific foods they consume around the time they notice an increase in their symptoms.

What are 3 symptoms of IBS?

The three most common IBS symptoms are:

  • abdominal pain
  • diarrhea
  • constipation

Other symptoms can include bloating, mucus in the stool, and feeling like the bowel is not completely empty.

Learn more about the signs and symptoms of IBS.

Can IBS go away?

A person’s IBS symptoms will not usually completely go away. However, most people with IBS can manage and reduce their symptoms with treatments and lifestyle or dietary methods.

Scientists have not yet found out exactly what causes IBS. Some risk factors that may make a person more likely to develop it include stressful early life events, some medical conditions, and mental health conditions.

Stress and some foods are more likely to trigger a person’s IBS symptoms. Medications, dietary changes, and lifestyle modifications may help a person with IBS manage their symptoms and reduce the frequency or severity of flare-ups.