<prompt> Most common site of ulcerative colitis is?RectumCaecumSmall intestineAppendix  <response>: ANSWER: A RectumREF: Harrison s 18th ed ch: 295UC is a mucosal disease that usually involves the rectum and extends proximally to involve all or part of the colon. About 40-50 of patients have disease limited to the rectum and rectosigmoid, 30-40 have disease extending beyond the sigmoid but not involving the whole colon, and 20 have a total colitis 