Outpatient colonoscopy has been proven safe but can rarely be associated with serious complications. The addition of polypectomy to the procedure increases the incidence of all complications with hemorrhage accounting for approximately half. The use of electrocautery for hot biopsy or polyp removal can result in a full-thickness burn without perforation in approximately 1 per cent of cases and typically presents as focal peritonitis without pneumoperitoneum. This so-called "postpolypectomy syndrome" or "serositis" is often successfully managed medically with resolution of symptoms in 24 to 48 hours. Bowel perforation occurs in less than 1 per cent of patients but requires emergent laparotomy. Appendicitis, both acute and perforated, has been reported as a rare complication of colonoscopy.