ocr: Resident and Staff nySICIOM Patiant Education Chart Discussion of Colonoscopy Colonoscopy is the visual examination of the colon by means of a flexible tube to determine the cause of bleeding and diagnose bowel disease. For the examination, the patient is usually sedated and lies on the left side. Reprinted with permissionfrom Resident and Staff Physician (c)1991-92, 19931 by Romaine Pierson Publishers, Inc.