Inflammatory bowel disease (IBD) refers to chronic conditions that cause inflammation in the lining and, in some instances, the wall of the intestine. The 2 primary types of IBD are:

Ulcerative colitis—This type causes inflammation and ulcers in the top lining of the colon and rectum.

Ulcerative Colitis

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Crohn’s disease—This type causes inflammation and ulcers in the lining and the wall of any part of the gastrointestinal tract. Crohn's disease usually affects the small intestine, particularly the last section (called the ileum). However, any part of the gastrointestinal tract—from the mouth to the anus—can be affected. The inflammation associated with Crohn’s disease reaches deeper into the layers of the intestinal wall, as opposed to ulcerative colitis, which affects primarily the lining of the intestine.

Crohn's Disease

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The cause of inflammatory bowel disease is not known. It seems to run in some families. Some researchers think that an infection causes the immune system to overreact and damage the intestines.

The Crohn's & Colitis Foundation of America estimates that as many as one million Americans may have inflammatory bowel disease—about half of these people have Crohn’s and the other half have ulcerative colitis.

Increased Risk of Colon Cancer

About 5% of people with ulcerative colitis eventually develop colon cancer. The risk of cancer increases with the duration and the extent of involvement of the colon. The risk is higher in those with ulcerative colitis with involvement of the entire colon and in those who have had the disease over 8-10 years.

Complications of Crohn’s Disease

Possible complications of Crohn’s disease include intestinal obstruction and formation of fistulas. A fistula is an abnormal connection between the intestine and other organs or tissues, such as the bladder, vagina, or skin.