Colitis is an inflammation of the large intestine (colon).


Colitis is an inflammation of the large intestine that can be caused by many different disease processes. These processes include acute and chronic infections, inflammatory disorders (ulcerative colitis, Crohn's colitis, lymphocytic and collagenous colitis), lack of blood flow (ischemic colitis), and history of radiation to the large bowel.

For more information about a specific type of colitis see:


Symptoms can include abdominal pain, diarrhea, dehydration, abdominal bloating, increased intestinal gas, and bloody stools.

Exams and Tests

Colitis may be identified by flexible sigmoidoscopy or colonoscopy  -- in both of these tests, a flexible tube is inserted in the rectum, and specific areas of the colon are evaluated. Biopsies taken during these tests may show changes related to inflammation.

Other studies that can identify colitis include:

  • Barium enema 
  • Abdominal CT scan 
  • Abdominal MRI 
  • Abdominal x-ray


Treatment is directed at the underlying cause of disease, whether it be infection, inflammation, lack of blood flow, or another cause.

See particular conditions listed above for specific recommendations.

Outlook (Prognosis)

The prognosis varies with each disease. See particular conditions listed above.

Possible Complications

Colitis may result in bleeding, ulceration, perforation (a hole in the colon), or toxic megacolon

When to Contact a Medical Professional

Call your health care provider if you have symptoms like abdominal pain, abdominal distention, or blood in the stool.


Prevention depends upon the underlying cause of colitis. See the specific condition.

Gastroenteritis - viral
Common peroneal nerve dysfunction
Meningitis - syphilitic
Congestive heart failure - right-sided
Chronic glomerulonephritis
Congenital megacolon
Dead bowel
Aortic aneurysm - dissecting

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