Irritable Bowel Syndrome (IBS ) Symptoms and Treatments

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What is irritable bowel syndrome (IBS)?

Irritable bowel syndrome (IBS) is a term used to describe discomfort in the bowel (the colon, or large intestine). Symptoms of IBS may include crampy pain, bloating, gas, mucus in the stool, and changes in bowel habits. Some people with IBS have constipation—infrequent stools that may be hard, dry and painful. Others have diarrhea—frequent loose stools. Some people having alternating constipation and diarrhea.

Sometimes a person with IBS has a crampy urge to move the bowels but cannot do so.

You may have heard IBS referred to as "spastic colon" or "spastic bowel." Sometimes IBS is confused with inflammatory bowel diseases such as ulcerative colitis. But IBS is not a disease and does not cause inflammation, bleeding, damage to the bowel, or cancer or other serious diseases. It is called a functional disorder, which means that there is no sign of disease when the colon is examined, but the bowel doesn't work as it should. The cause of IBS is not known, and as yet there is no cure.

Often IBS is just a mild annoyance, but for some people, it can be disabling. They may be unable to go to social events, to go out to a job, or to travel even short distances. Most people with IBS, however, are able to control their symptoms through diet, stress management, and medicines.

Who gets IBS?

IBS is a common problem, affecting up to one in five people.

However, estimates of the number of people with IBS vary. The majority of people with IBS (perhaps 75 percent) are women. IBS often begins in the teen years or young adulthood but can affect people of any age.

What are the symptoms of IBS?

Symptoms of IBS may include:

  • Crampy pain in the abdomen

  • Constipation

What causes IBS symptoms?

The colon or large intestine is a muscular tube about 6 feet long. It connects the small intestine with the rectum and anus.

The colon absorbs water and salts from digested food after it has traveled from the stomach through the small intestine. The muscles of the colon contract (tighten or squeeze) and gradually move the material toward the rectum. Strong contractions then lead to a bowel movement. Colon contractions are controlled by nerves, hormones, and by electrical activity in the muscles.

Researchers have found that, for unknown reasons, the colons of people with IBS are more sensitive than usual, and react to things that would not bother other people. For example, the muscles may contract too much after eating. These contractions can cause cramping and diarrhea during or shortly after a meal. The nerves can be overly sensitive to the stretching of the bowel (because of gas, for example), causing cramping or pain.

Diet and stress play a role in IBS for many people, causing symptoms or making them worse.

In women, IBS symptoms may be worse during their menstrual periods, so hormone changes may be involved. Sometimes IBS symptoms appear after another illness.

How is IBS diagnosed?

IBS usually is diagnosed after bowel disease has been ruled out. Your doctor will probably take a complete medical history, do a physical exam, and check for blood in your stool. Other diagnostic tests such as blood tests, x-rays or a colonoscopy (viewing the colon through a flexible tube inserted through the anus) may be done if needed.

How do diet and stress affect IBS?

In people with IBS, diet and stress often seem to cause symptoms. Many people report that their symptoms occur after a meal or when they are under stress. No one is sure why this happens, but scientists have some clues.

Eating causes contractions or spasms of the colon. Normally, this response may cause an urge to have a bowel movement within 30 to 60 minutes after a meal.

In people with IBS, the urge may come sooner with cramps and diarrhea. Contractions may be stronger after a large meal or a meal with a lot of fat in it. Many people with IBS learn to avoid certain foods, beverages, and medicines that seem to make their symptoms worse.

Stress can cause contractions of the colon in people with IBS. The reasons for this are not clear, but scientists point out that the colon is controlled partly by the nervous system. Learning relaxation methods and other ways to reduce stress can be helpful. Counseling and support help relieve IBS symptoms in many people.

What foods may cause IBS symptoms?

Some foods that may cause symptoms include:
  • Fatty foods like french fries

  • Milk products like cheese or ice cream (especially in people who have trouble digesting lactose, or milk sugar)

  • Chocolate

  • Alcohol

  • Caffeine (found in coffee, tea, and some sodas)

  • Carbonated drinks like soda

  • Sorbitol, a sweetener found in dietetic foods and in some chewing gums

  • Gas-producing foods including beans and certain vegetables like broccoli or cabbage.

You may want to keep a journal keeping track of the foods that seem to cause trouble. If certain foods cause your symptoms to flare up, you can try eating less of those foods.

Discuss your findings with your doctor. You also may want to consult a registered dietitian, who can help you make changes in your diet.

What can I do to help my IBS besides avoiding problem foods and beverages?

Drinking lots of water and increasing your fiber intake may help, especially if constipation is a problem. Fiber is found in bran, bread, cereal, beans, fruits, and vegetables. It's a good idea to increase the fiber in your diet gradually to avoid causing gas and pain. Many people with IBS also use a fiber supplement to add soluble fiber, often from psyllium seeds, to the diet.

Regular exercise can help with constipation and improve your health in other ways. Look into support groups, stress reduction methods or counseling if you think they might be helpful. Be careful about using laxatives, anti-diarrhea or other over-the-counter medicines to treat yourself. They can cause problems if misused. Other kinds of medicines sometimes make IBS symptoms worse, too.

What medicines are used to treat IBS?

Medicines sometimes used for IBS symptoms include:
  • antispasmodics—drugs that control colon muscle spasms and help with diarrhea and pain

  • tranquilizers and antidepressants to help with stress, anxiety, and depression.

Be sure to follow your doctor's instructions for use of all medicines. Some medicines including laxatives can be habit-forming, and all drugs have side effects. Tell your doctor about any over-the-counter medicines that you use. New drugs are being developed for IBS—ask your doctor about new treatment options.

For more information about irritable bowel syndrome, contact the National Women's Health Information Center at (800) 994-WOMAN (9662) or the following organizations:

National Digestive Diseases Information Clearinghouse, NIDDK, NIH HHS
Phone Number(s):(301) 654-3810, (800) 891-5389
Web Site:

National Library of Medicine—Medlineplus
Web site:

American Society of Colon and Rectal Surgeons
Phone Number(s): (847) 290-9184
Web Site:

American College of Gastroenterology
Phone Number(s): (703) 820-7400
Web Site:

The information in this FAQ was adapted primarily from materials from the National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK), including "Irritable Bowel Syndrome" and "What I Need to Know about Irritable Bowel Syndrome."

Reprinted from the Office on Women's Health in the Department of Health and Human Services.

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