Many methods are being considered for the endoscopic control of upper gastrointestinal bleeding. These techniques can stop experimental bleeding without adverse clinical effects in animals. Some techniques penetrate more deeply than others and therefore have a higher incidence of full-thickness wall injury, but these techniques may also be most useful for a deep-lying vessel which requires greater penetration of energy through tissue. There are many questions that will only be answered in carefully controlled clinical trials comparing new methods with standard therapy and new therapies with each other; however, each method must first be found to be effective and safe in animal studies. We hope that eventually one or more endoscopic hemostatic method will prove clinically safe and effective and improve the outcome for patients with upper gastrointestinal bleeding.