Irritable bowel syndrome (IBS) is a disorder that leads to abdominal pain and bowel changes.
IBS is not the same as inflammatory bowel disease (IBD).
The reasons why IBS develop are not clear. It can occur after an infection of the intestines. This is called postinfectious IBS. There may also be other triggers.
The intestine is connected to the brain. Signals go back and forth between the bowel and brain. These signals affect bowel function and symptoms. The nerves can become more active during stress. This can cause the intestines to be more sensitive and contract more.
IBS can occur at any age. Often, it begins in the teen years or early adulthood. It is twice as common in women as in men.
About 1 in 6 people in the U.S. have symptoms of IBS. It is the most common intestinal problem that causes patients to be referred to a bowel specialist (gastroenterologist).
IBS symptoms vary from person to person and range from mild to severe. Most people have mild symptoms. You are said to have IBS when symptoms are present for at least 3 days a month for a period of 3 months or more.
The main symptoms include:
Pain and other symptoms will often be reduced or go away after a bowel movement. Symptoms may flare up when there is a change in the frequency of your bowel movements.
People with IBS may go back and forth between having constipation and diarrhea or have or mostly have one or the other.
The symptoms may get worse for a few weeks or a month, and then decrease for a while. In other cases, symptoms are present most of the time.
You may also lose your appetite if you have IBS.
There is no test to diagnose IBS. Most of the time, your doctor can diagnose IBS based on your symptoms. Eating a lactose-free diet for 2 weeks may help the doctor identify lactase deficiency.
The following tests may be done to rule out other problems:
Your doctor may recommend a colonoscopy. During this test, a flexible tube is inserted through the anus to examine the colon. You may need this test if:
Other disorders that can cause similar symptoms include:
The goal of treatment is to relieve symptoms.
Lifestyle changes can help in some cases of IBS. For example, regular exercise and improved sleep habits may reduce anxiety and help relieve bowel symptoms.
Dietary changes can be helpful. However, no specific diet can be recommended for IBS, because the condition differs from one person to another.
The following changes may help:
Talk with your doctor before taking over-the-counter medications.
No one medicine works for everyone. Some that your doctor may suggest include:
Psychological therapy or medicines for anxiety or depression may help with the problem.
Irritable bowel syndrome may be a lifelong condition. For some people, symptoms are disabling and interfere with reduce work, travel, and social activities.
Symptoms often get better with treatment.
IBS does not cause permanent harm to the intestines. Also, it does not lead to a serious disease, such as cancer.
Call your health care provider if you have symptoms of irritable bowel syndrome or if you notice changes in your bowel habits that do not go away.
Reviewed By: George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.