Upper intestinal endoscopy is a well-accepted method for evaluation of the esophagus, stomach, and duodenum. The techniques are standardized and extremely safe. The therapeutic capability for control of gastrointestinal hemorrhage is a major advance in the treatment of gastrointestinal bleeding. Endoscopic ultrasound is useful in the staging of upper intestinal malignancies. Above all, the ability to directly visualize the mucosal lining, to obtain biopsies, and to remove polyps has made endoscopy a primary tool for investigation of upper gastrointestinal pathology.