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Articles » IBS: NIDDK


Article title: IBS: NIDDK

Conditions: Irritable bowel syndrome, bowel, abdomen

Source: NIDDK

What is IBS?

Irritable bowel syndrome, or IBS, is a problem that affects mainly the bowel, which is also called the large intestine. The bowel is the part of the digestive system that makes and stores stool. The word syndrome means a group of symptoms. IBS is a syndrome because it can cause several symptoms. For example, IBS causes cramping, bloating, gas, diarrhea, and constipation.

Medical words are defined in the glossary.

IBS is not a disease. It's a functional disorder, which means that the bowel doesn't work as it should.

With IBS, the nerves and muscles in the bowel are extra-sensitive. For example, the muscles may contract too much when you eat. These contractions can cause cramping and diarrhea during or shortly after a meal. Or the nerves can be overly sensitive to the stretching of the bowel (because of gas, for example). Cramping or pain can result.

IBS can be painful. But it does not damage the bowel or cause any other diseases.

Does stress cause IBS?

Emotional stress will not cause a person to develop IBS. But if you already have IBS, stress can trigger symptoms. In fact, the bowel can overreact to all sorts of things, including food, exercise, and hormones.

Foods that tend to cause symptoms include milk products, chocolate, alcohol, caffeine, carbonated drinks, and fatty foods. In some cases, simply eating a large meal will trigger symptoms.

Women with IBS often have more symptoms during their menstrual periods.

What are the symptoms of IBS?

The main symptoms of IBS are

  • Crampy pain in the stomach area (abdomen)
  • Painful diarrhea or constipation

Most people have either diarrhea or constipation, but some people have both.

Other symptoms are

  • Mucus in the stool
  • Swollen or bloated abdomen
  • The feeling that you have not finished a bowel movement

How is IBS diagnosed?

The doctor will suspect that you have IBS because of your symptoms. But the doctor may do medical tests to make sure you don't have any other diseases that could cause the symptoms.

Medical tests for IBS

  • Physical exam
  • Blood tests
  • X ray of the bowel: This x-ray test is called a barium enema or lower GI (gastrointestinal) series. Barium is a thick liquid that makes the bowel show up better on the x ray. Before taking the x ray, the doctor will put barium into your bowel through the anus.
  • Endoscopy: The doctor inserts a thin tube into your bowel. The tube has a camera in it, so the doctor can look at the inside of the bowel to check for problems.

What is the treatment?

IBS has no cure, but you can do things to relieve symptoms. Treatment may involve

  • diet changes
  • medicine
  • stress relief

You may have to try a combination of things to see which works best for you.

Diet changes

Some foods make IBS worse.

Here are some foods that may cause symptoms:

  • Fatty foods like french fries
  • Milk products like cheese or ice cream
  • Chocolate
  • Alcohol
  • Caffeine (found in coffee and some sodas)
  • Carbonated drinks like soda

These foods may make IBS worse.

If certain foods cause symptoms, you should eat less of them or stop eating them.

To find out which foods are a problem, write down this information:

  • What you eat during the day.

  • What symptoms you have.

  • When symptoms occur.

  • What foods always make you feel bad.

Take your notes to the doctor to see if you should stop eating certain foods. Some foods make IBS better.

Fiber reduces IBS symptoms--especially constipation--because it makes stool soft, bulky, and easier to pass. Fiber is found in bran, bread, cereal, beans, fruit, and vegetables.

Here are some examples of foods with fiber:

Fruits Vegetables Breads, cereals, and beans
Broccoli, raw
Carrots, raw
Kidney beans
Lima beans
Whole-grain bread
Whole-grain cereal

Add foods with fiber to your diet a little at a time to let your body get used to them. Too much fiber all at once might cause gas, which can trigger symptoms in a person with IBS.

Besides telling you to eat more foods with fiber, the doctor might also tell you to get more fiber by taking a fiber pill or drinking water mixed with a special high-fiber powder.

How much you eat matters, too.

Large meals can cause cramping and diarrhea in people with IBS. If this happens to you, try eating four or five small meals a day. Or, have your usual three meals, but eat less at each meal.


If necessary, the doctor might give you medicine to help with symptoms:

  • Laxatives: To treat constipation.
  • Antispasmodics: To slow contractions in the bowel, which helps with diarrhea and pain.
  • Antidepressants: To help those who have severe pain.

You must follow your doctor's instructions when you use these medicines. Otherwise, you could become dependent on them.

Stress relief

Does stress trigger your symptoms? Learning to reduce stress can help. With less stress, you may find that you have less cramping and pain. Also, you may find it easier to manage your symptoms.

Meditation, exercise, and counseling are some things that might help. You may need to try different activities to see what works best for you.

Points to remember

  • IBS is a functional disorder in which the bowel doesn't work as it should.
  • IBS can cause cramping, bloating, gas, diarrhea, and constipation.
  • IBS doesn't damage the bowel.
  • The doctor will diagnose IBS based on your symptoms. You might have some medical tests to rule out other diseases.
  • Stress doesn't cause IBS, but it can trigger symptoms.
  • Fatty foods, milk products, chocolate, caffeine, carbonated drinks, and alcohol can trigger symptoms.
  • Eating foods with fiber and eating smaller meals can reduce symptoms.
  • Treatment for IBS may include medicine, stress relief, or changes in eating habits.


Abdomen (AB-doh-men): The area of the stomach.

Barium enema (BAR-ee-um EN-uh-muh): An x ray of the bowel using a liquid called barium to make the bowel show up better. This test is also called an upper GI (for gastrointestinal) series.

Bowel: The part of the digestive system that makes and stores stool. It is also called the large intestine.

Endoscopy (en-DAH-skuh-pee): A test to look at the inside of the bowel.

Functional: Refers to how something works.

Mucus: A clear, sticky discharge. It might look white.

Syndrome(SIN-drome): A group of symptoms.

For more information

More information about IBS is available from

International Foundation for Functional Gastrointestinal Disorders (IFFGD)
P.O. Box 17864
Milwaukee, WI 53217
Phone: (414) 964-1799 or 1-888-964-2001
Fax: (414) 964-7176

Also, the National Digestive Diseases Information Clearinghouse (NDDIC), which prepared this booklet, has a fact sheet on IBS. You can get a copy by contacting

2 Information Way
Bethesda, MD 20892-3570
Phone: 1-800-891-5389 or (301) 654-3810
Fax: (301) 907-8906


The individuals listed here provided editorial guidance or facilitated field testing for this publication. The National Digestive Diseases Information Clearinghouse would like to thank them for their contribution.

Nancy Norton
International Foundation for Functional Gastrointestinal Disorders
Milwaukee, WI

Douglas A. Drossman, M.D.
UNC Center for Functional GI and Motility Disorders
University of North Carolina
Chapel Hill, NC

Salvation Army, SE Corps
Washington, DC

National Digestive Diseases Information Clearinghouse

2 Information Way
Bethesda, MD 20892-3570

The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health under the U.S. Department of Health and Human Services. Established in 1980, the clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.

Publications produced by the clearinghouse are carefully reviewed by both NIDDK scientists and outside experts.

This e-text is not copyrighted. The clearinghouse encourages users of this e-pub to duplicate and distribute as many copies as desired.

NIH Publication No. 01-4686
March 2001

Posted: May 2001


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