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Colitis (ko-LY-tis) is the general term meaning inflammation of the lining of the colon (the lower part of the large intestine) and the rectum.


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Digestive system




What Is Colitis?

Colitis is a type of inflammatory * bowel disease that affects mainly the large intestine and the rectum * . Different types of colitis may be chronic or acute and may have different causes, but they have many symptoms in common, including diarrhea that may be bloody. Many people also feel abdominal pain and cramping.

Acute colitis

Acute colitis has many different causes, including:

  • Bacteria from contaminated food and water: As the bacteria grow, they release poisons (toxins) that cause the lining of the bowel to become sore and inflamed.
  • Antibiotics: Antibiotics used to treat specific bacterial infections also may kill helpful bacteria that occur naturally in the intestines. This can allow harmful intestinal bacteria to grow more abundantly and to cause acute colitis.
  • Insufficient blood flow to the colon: This is known as ischemic colitis and may have a wide range of causes.
  • Heavy doses of radiation to the lower abdomen: Called radiation enterocolitis, this may occur long after radiation therapy has been completed.

Acute colitis lasts for a short time, then goes away on its own or is cured by treatment.

Chronic colitis

The exact causes of chronic colitis are not always known. Scientists think that the body's immune system may react inappropriately to a virus or bacteria, causing the lining of the intestine to become and to remain inflamed. Chronic colitis is ongoing and long-lasting. In many cases it cannot be cured, although treatments are available that may help relieve a person's symptoms.

Ulcerative colitis is an example of chronic colitis. Persistent, small, bloody sores (ulcers) usually form on the inside lining of the colon or rectum. Many people with ulcerative colitis have mild symptoms, but others may have frequent, severe symptoms that can disrupt their daily lives.

How Is Colitis Diagnosed and Treated?

The symptoms of colitis are similar to those of other inflammatory bowel diseases such as Crohn's disease (ileitis).

* inflammation is the body's reaction to irritation, infection, or injury that often involves swelling, pain, redness, and warmth.

* rectum is the final portion of the large intestine, connecting the colon to the outside opening of the anus.


A thorough physical examination, medical history, and diagnostic tests are needed to make an accurate diagnosis of colitis. Stool samples are usually examined for evidence of blood or infection. Often the colon is examined through a procedure called colonoscopy (kol-on-OS-ko-pee). An endoscope, or lighted flexible tube and camera attached to a television monitor, is inserted through the anus. This allows the doctor to see the inside lining of the colon and rectum. During the colonoscopy, the doctor may remove a tissue sample (called a biopsy) from the intestinal lining for further examination under the microscope.


Treatment for acute colitis depends on its cause. Although chronic colitis may not be cured, many people's symptoms are treated effectively with prescription medications that reduce inflammation in the colon and rectum and control diarrhea.

Some people find their symptoms improve if they change their diet. Many people with chronic colitis have periods of months or years when their symptoms go into remission (go away). Very severe cases of colitis may require surgery to remove the damaged portion of the colon and limit intestinal bleeding.

See also
Colorectal cancer
Diverticulitis and Diverticulosis
Inflammatory Bowel Disease
Irritable Bowel Syndrome


U.S. National Digestive Diseases Information Clearinghouse, 2 Information Way, Bethesda, MD 20892-3570. This division of the National Institutes of Health posts fact sheets about ulcerative colitis and Crohn's disease at its website.

Crohn's and Colitis Foundation of America, Inc., 386 Park Avenue South, New York, NY 10016-8804.
Telephone 800-932-2423

Also read article about Colitis from Wikipedia

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