Ulcerative colitis, one of the idiopathic inflammatory bowel disease, is a chronic disease that affects the mucosa of rectum and colon. It occurs more commonly in developed countries. The incidence of disease has remained relatively stable during the past 25 years. It commonly affects patients in their youth or early middle age. Dietary and environmental factors play role in etiology. Ulcerative colitis typically presents with periods of remissions and exacerbations characterized by rectal bleeding and diarrhea. The disease can have serious long term local and systemic consequences. Complications include massive bleeding, fulminant colitis with toxic megacolon, intestinal perforation, dysplasia and carcinoma. Risk of colonic perforation with toxic dilatation in patients of ulcerative colitis is 10%. Early surgical intervention is required for reducing mortality.