Colonic ischemia encompasses a wide clinical spectrum from mild, reversible disease to severe, irreversible injury. It is a frequent disorder of the large bowel in the elderly, and can mimic certain diseases such as inflammatory bowel disease and neoplasms. The clinical course is variable, but often includes crampy, lower abdominal pain and the passage of red or maroon blood mixed with stool. In most cases, management is expectant, with supportive care and attention for signs of complicated disease. Prognosis typically is favorable, with a majority of patients completely resolving their illness; a minority go on to develop irreversible injury including strictures and chronic segmental colitis. Successful management of a patient with ischemic colitis requires a high degree of clinical suspicion, early diagnosis, careful follow-up, and prompt recognition of persistent disease.