Colitis is Inflammation of the colon. Infection with viruses, bacteria, or parasites may cause it, often with enteritis. Inflammatory colitis can occur without bacterial infection in the chronic diseases, ulcerative colitis and Crohn's disease. Impaired blood supply may also cause colitis. Symptoms include colic and diarrhea (with slime or blood). Severe colitis can cause serious dehydration or shock. Treatments include antibiotics, and, for inflammatory colitis, steroids, aspirin derivatives, or, occasionally, surgery.