A randomized trial comparing the efficacy of BICAP electrocoagulation and YAG laser photocoagulation was carried out in 100 patients presenting at endoscopy with peptic ulcer and a spurting or oozing vessel or a nonbleeding vessel. Fifty patients were enrolled in each treatment group. All lesions were pretreated with injection of epinephrine 1:10,000. Subsequently, 1-sec pulses of 80 watt YAG laser power were applied to the vessel or 1- to 2-sec pulses of electrocoagulation of 25 watt BICAP at a setting of 10. The 10 F BICAP probe was always used. Definitive hemostasis after one treatment amounted to 72% in both the laser and in the BICAP group. After two sessions the cumulative success rate was 88% in the laser group and 86% in the BICAP group. Emergency surgery and mortality were also comparable. One perforation occurred in each treatment group and both patients were operated upon without complications. It is concluded that both YAG laser and BICAP are highly and equally effective in the treatment of severe bleeding from peptic ulcers. This study stresses the importance of repeated treatment sessions in order to obtain optimal results.