Several methods of endoscopically controlling acute, nonvariceal upper gastrointestinal bleeding have been developed. Some, such as the laser, heater probe, and bipolar electrocoagulation, have been evaluated in controlled clinical trials. The purpose of this paper is to discuss endoscopic control of nonvariceal gastroduodenal hemorrhage and to consider whether improvement in outcome is likely with any of these devices. Techniques and results of controlled clinical trials are reviewed.