Ulcerative colitis is an idiopathic, chronic progressive inflammatory bowel disease of colonic mucosa, that causes the rectum and colon (Sigmoid colon) forms range from mild to severe. This chapter encompass the Ulcerative colitis- An overview. It can occur in people of any age usually in between ages of 15-30 years unless frequently in 50 years. The cause is complex and involves many factors, abnormal immune response against some micro-organisms, other environmental factors. Early diagnosing of UC with signs and symptoms like Diarrhea, Bloody stools with endoscopy biopsy. Proper treatment and medication, management, hygiene may be at lower risk. Other complication may cause Colon cancer and can be life-threatening with other co-morbidities.