Gastroenterologists and Colon and Rectal Surgeons use endoscopic procedures to diagnose and treat patients who may have digestive disease. Gastrointestinal endoscopy is the examination of the digestive tract with a flexible, lighted instrument called an endoscope. Using an endoscope, physicians can directly visualize the esophagus, stomach, portions of the small intestine and the colon. Endoscopes allow physicians to more accurately diagnose and treat diseases of the digestive system. Using endoscopes, physicians can take biopsies, dilate narrowed areas called strictures, and remove polyps, which are growths in the digestive.