Ulcerative colitis (UC) is a disorder characterized by diffuse mucosal inflammation limited to the colon. UC is usually a chronic disease which involves the rectum and may extend proximally in a symmetrical, circumferential, and uninterrupted pattern to involve parts or all of the large intestine. The hallmark clinical symptom is bloody diarrhea often with prominent symptoms of rectal urgency and tenesmus (painful straining at stool). The clinical course is marked by exacerbations and remissions, which may occur spontaneously or in response to treatment changes or intercurrent illnesses  . Ulcerative colitis affects approximately 250,000 individuals in the United States with an incidence of 2-6 per 100,000 people per year; the prevalence has remained relatively constant over the last five decades.