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Irritable Bowel Syndrome

(Functional Colitis; IBS; Intestinal Neurosis; Irritable Colon; Laxative Colitis; Mucous Colitis; Spastic Colon)


Irritable bowel syndrome (IBS) is a chronic disorder of the intestines. IBS does not cause inflammation and does not lead to a more serious condition.

Causes    TOP

The cause is unknown. With IBS, the muscles in the colon do not work normally and may spasm. If you have IBS, your colon may be more sensitive, reacting strongly to food and medication. Food allergies and certain bacteria may add to the symptoms. IBS may also occur after having the stomach flu (called gastroenteritis).

Risk Factors    TOP

IBS is more common in women. It typically begins in young adulthood.

These factors may increase your chance of developing IBS:

Symptoms    TOP

Symptoms usually come and go, and range from mild to severe. They include:

  • Abdominal cramps
  • Gas and bloating
  • Pain that resolves with a bowel movement
  • Loose stools
  • Diarrhea
  • Constipation
  • Alternating diarrhea and constipation
  • Urge to move bowels again immediately following a bowel movement
  • Mucus in the stool

These factors may worsen your symptoms:

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

Diagnosis    TOP

You will be asked about your symptoms and medical history. A physical exam will be done. In many cases, a diagnosis can be made based on this. Since there is no diagnostic test for IBS, doctors have created criteria for making a diagnosis.

Your bodily fluids and waste products may be tested. This can be done with:

  • Stool tests
  • Blood tests

Your body structures may need to be viewed. This can be done with:


Colonoscopy scope
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Treatment    TOP

There is no cure for IBS. Treatment focuses on controlling symptoms.


The following changes to your diet may help control symptoms:

  • Keep a food diary of what you eat and how your body responds. Share this with your doctor. You may have a food allergy.
  • Make gradual changes to your diet. Record the results.
  • Avoid foods that have caused problems in the past. A dietitian can help you substitute foods.
  • Avoid foods and drinks that may cause symptoms:
    • High fat foods, spicy foods
    • Dairy products
    • Onions, cabbage, and other gas-producing food
    • Large amounts of alcohol or caffeine
  • Eat foods that may reduce the chance of spasm, such as:
  • Eat smaller meals more often or smaller portions.
  • Eat slowly and try not to swallow air.
  • Drink plenty of water. This will help to reduce constipation.


Participating in a regular exercise program can help improve bowel function and other IBS symptoms. If you would like to start exercising, check with your doctor to make sure you are healthy enough.

Stress Management    TOP

Talk to your doctor about ways to reduce stress, such as:

Education    TOP

Learn as much as you can about IBS and ways that you can reduce your symptoms. You may also find it helpful to join a support group.

Medication    TOP

Depending on your symptoms, your doctor may recommend:

  • Antispasmodic agent
  • Antibiotics
  • High-fiber bulking agent
  • Antiflatulent
  • Antidiarrheal agent
  • Low-dose antidepressant
  • Pain reliever
  • Serotonin receptor agonists and antagonists (also called 5-HT3 antagonists)—may be helpful for treating diarrhea, as well as treating other IBS symptoms, like abdominal pain in women
  • Probiotics
  • Peppermint oil

In some cases, your doctor may recommend that you take a combination of medications.

Prevention    TOP

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


American College of Gastroenterology
American Gastroenterological Association


Canadian Digestive Health Foundation


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Last reviewed December 2015 by Daus Mahnke, MD
Last Updated: 12/20/2014