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JAMA Patient Page
August 18, 2004

Irritable Bowel Syndrome

JAMA. 2004;292(7):886. doi:10.1001/jama.292.7.886

Irritable bowel syndrome (IBS) is a gastrointestinal (digestive) problem that affects up to 15% of adults (during their lifetimes) in developed countries. Irritable bowel syndrome is a functional disorder, meaning that tests do not reveal a cause in the structure of the bowel such as an obstruction or a tumor. Irritable bowel syndrome is completely different from Crohn disease or ulcerative colitis, which are inflammatory diseases of the intestine. Having IBS does not increase the risk of developing colon cancer. Gastroenterologists (doctors with specialized training in treating disorders of the bowel and other digestive organs) may be consulted to help diagnose and treat IBS. The August 18, 2004, issue of JAMA includes an article about IBS that reviews evidence that IBS may be related to abnormal fermentation (chemical breakdown) of food by bacteria inside the bowel.


  • Bloating and gas (particularly after eating)

  • Abdominal cramping

  • Constipation

  • Diarrhea

  • Urgency to have a bowel movement, sometimes right after having one

  • Abnormal stool form (including the passage of mucus)

Medical testing may be done to rule out other causes of these symptoms. Blood in the stool is an important reason to see your doctor. It is not a typical symptom of IBS.


  • Stress

  • Eating a large meal

  • High-fat or high-fiber meals

  • Menstrual periods

If your symptoms become worse after drinking milk or eating other dairy products, you may have lactose intolerance. This intolerance is the inability to digest the sugars (lactose) found in milk and is not part of IBS. Foods themselves do not cause IBS. However, persons with IBS may find that certain foods make their symptoms worse.


  • Reduce stress.

  • Eat a healthful, balanced diet and avoid foods that trigger an increase in your symptoms.

  • Small meals during the day (instead of 3 large meals) may be beneficial.

  • Engage in regular physical exercise.

  • Medications called antispasmodics may be prescribed to decrease the spasms in the bowel and reduce diarrhea symptoms.

  • A prescription medication is available for short-term use in women with IBS whose primary symptom is constipation.



To find this and previous JAMA Patient Pages, go to the Patient Page Index on JAMA's Web site at Many are available in English and Spanish. A Patient Page on colon cancer screening was published in the March 12, 2003, issue.

Sources: National Institute of Diabetes and Digestive and Kidney Diseases, American Academy of Family Physicians, Irritable Bowel Syndrome Association, International Foundation for Functional Gastrointestinal Disorders

The JAMA Patient Page is a public service of JAMA. The information and recommendations
appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. Any other print or online reproduction is subject to AMA approval. To purchase bulk reprints, call 718/946-7424.