Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a disorder that affects the large intestine (colon). It is more common in women than men and often starts around age 20. IBS can be painful but does not permanently harm the intestines, cause intestinal bleeding, or lead to serious health conditions or diseases.


IBS is usually characterized by abdominal pain and discomfort that is often accompanied by constipation and/or diarrhea. Other symptoms include:

  • cramping pain in the abdomen
  • swollen or bloated abdomen
  • mucus in the stool
  • the feeling that a bowel movement is not finished
  • a sense of urgency to have a bowel movement
  • relief of symptoms after a bowel movement
  • worsening of symptoms during the menstrual period


IBS has no known single cause. Research indicates that those with IBS have a colon that is more sensitive and reacts more to a variety of things, including certain foods and stress, though the cause of this sensitivity remains unclear. The IBS symptoms themselves result from changes in the normal motion of the colon; it may either be too fast, which leads to diarrhea, or too slow, which leads to constipation. It may also spasm, which causes strong muscle contractions and cramping.


IBS is diagnosed based on a complete medical history, including a description of symptoms and a physical exam. Diagnostic tests may be used to rule out other problems, but testing is not necessary to diagnose IBS.


Because there is no cure for IBS, treatment is aimed at alleviating symptoms. Sometimes medication may be prescribed by a clinician.

General treatment measures

Stress management:

Stress can trigger symptoms of IBS. Managing stress can improve the functioning of the GI tract’ s nervous system and is an important part of treatment. Research shows that cognitive behavioral therapy may be particularly helpful in managing stress. Other options for managing stress include:

  • Try to sleep at least 6 to 8 hours a night.
  • Exercise regularly.
  • Meditate or practice yoga daily.

Diet changes:

Some foods, such as fatty foods, foods high in fructose, or dairy products, may worsen IBS symptoms. If certain foods cause symptoms, eat less of them or avoid them completely. Keep a list of troublesome foods in a journal and discuss them with a clinician or dietitian.

Try some of the following dietary changes to help alleviate IBS symptoms:

  • Avoid carbonated beverages, which can produce gas and cause discomfort.
  • Drink six to eight glasses of water a day to treat constipation.
  • Avoid chewing gum and eating quickly, both of which can lead to swallowing air, which produces gas.
  • Eat smaller meals more often or smaller portions since large meals can cause cramping and diarrhea.
  • Include high-fiber foods such as whole grains, beans, fruits, and vegetables in the diet, which may reduce constipation and prevent spasms. To minimize gas and bloating, increase fiber intake slowly by two to three grams daily.

Nonprescription medications

Peppermint oil

Peppermint oil contains menthol, a chemical that relaxes smooth muscles in the GI tract. Research studies show that peppermint oil may be effective in reducing the amount of cramping and pain with IBS.

A common dose is 200 mg twice a day. Enteric-coated capsules are recommended since they dissolve lower in the GI tract, which means that they are less likely to cause heartburn or other reflux-related discomfort.

Fiber supplements

Fiber supplements have been commonly used to manage IBS symptoms, but recent studies have shown that they may not be as helpful as they seem. Taking fiber supplements increases the risk of gas and bloating.


Constipation that does not get better with lifestyle changes can be cautiously managed by the use of laxatives. These include stool softeners (docusate), colonic stimulants (bisacodyl, senna), and osmotic agents (polyethylene glycol, magnesium-containing compounds, lactulose). Polyethylene glycol and magnesium-based agents are safe, well-tolerated and can be used long-term.

Stool softeners may be useful when taken along with other treatments, although none of them will help with the cramps associated with IBS.

Anti-diarrheal drugs and others

  • Loperamide hydrochloride (Imodium): take 2 to 4 mg every morning. This can be increased or repeated if necessary, but do not exceed 8 pills daily.
  • Beano: an enzyme available in either pill or liquid form that helps reduce gas by breaking down indigestible carbohydrates such as those found in beans, cauliflower, and broccoli. Follow label directions.
  • Lactaid: contains lactase, an enzyme that helps digest the milk sugar lactose (found in most dairy products except yogurt and hard cheeses). Follow label directions.

Prescription medications

  • Tricyclic antidepressants (such as amitriptyline) may help reduce diarrhea and reduce pain when taken at doses much lower than necessary to treat depression.
  • Propantheline (Pro-Banthine) and dicyclomine (Bentyl) can help alleviate colon spasms. To prevent pain attacks, take the medication on an empty stomach or 30 minutes to 1 hour before meals.
  • Diphenoxylate (Lomotil) is a drug that can help prevent diarrhea when taken regularly throughout the day or after the first loose stool. Use of diphenoxylate may cause drowsiness or dizziness, so use caution before driving or operating machinery.

When to contact a clinician

Contact a clinician if any of these symptoms are present:

  • bleeding or blood in the stool
  • fever
  • weight loss
  • persistent and/or severe pain

[HU480: Updated 04/09]