Irritable Bowel Syndrome



With IBS, the muscles in the colon (large intestine) spasm. The exact cause is unknown. It may be due to a mix of things, such as:

  • Problems with how the digestive muscles contract and move food through the tract
  • Highly sensitive nerves in the digestive tract
  • Faulty signals between the brain and the gut

The colon may overreact to certain foods and medicine. Certain bacteria may add to the symptoms.

Risk Factors

IBS is more common in women. It typically begins in young adulthood. Things that may raise the risk of IBS are:

  • Family members with IBS
  • Food allergies or intolerances
  • Mental health problems such as stress, anxiety , or depression
  • A history of physical or sexual abuse
  • A history of a stomach or intestinal infection



Symptoms of IBS tend to come and go. They range from mild to severe and can include:

  • Belly cramps
  • Gas and bloating
  • Pain that goes away with passing stool (pooping)
  • Diarrhea—loose stools (poop)
  • Constipation—stools that are hard to pass
  • Bouts of diarrhea and constipation
  • Urge to pass stools again right after pooping
  • Mucus in the stools

Symptoms may get worse with:

  • Stress
  • Menstrual periods
  • Large meals or fatty foods
  • Excess gas


The doctor will ask about symptoms and past health. A physical exam will be done. There is no test for IBS. Doctors use a checklist of symptoms to make a diagnosis.

Stool and blood tests may be done to rule out other problems. Images of the intestines may also be taken with:

  • X-ray
  • Flexible sigmoidoscopy
  • Colonoscopy
Colonoscopy scope
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There is no cure for IBS. Treatment focuses on controlling symptoms. Options are:

Diet Changes

Certain foods and drinks may lead IBS to flare. The doctor will ask the person to keep a food diary. The person will track the foods they eat and how their body responds. They will slowly make some diet changes to see what helps. A dietitian can help with meal planning.

Foods that may be more likely to cause problems are:

  • High fat foods, spicy foods
  • Dairy products
  • Onions, cabbage, and other gas-producing food
  • Large amounts of alcohol or caffeine

Foods that may reduce risk of spasms include:

  • Fruits and vegetables
  • Whole grains and other high-fiber foods—may need to be added slowly

Each person with IBS is different. What helps one person may not help another.

Physical Activity and Stress Management

Regular physical activity can help improve intestine function. This may ease IBS symptoms.

Stress and tension can make symptoms worse. Relaxation methods may help.

Groups for people with IBS offer information and support. They may also help ease stress.


The doctor may advise medicines to:

  • Stop muscle spasms in the gut
  • Treat bacteria that makes IBS worse
  • Add fiber—to make hard stools easier to pass
  • Relieve gas
  • Reduce diarrhea
  • Ease anxiety, stress, and depression
  • Relieve pain

Some people find other treatments helpful such as:

  • Probiotics—bacteria help rebalance the normal bacteria in the colon
  • Peppermint oil


There are no current guidelines for preventing IBS because the cause is unknown.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.