We carried out a prospective, randomized, controlled trial over a 7-month period to assay the hemostatic effects of octreotide and heater probe thermocoagulation (HPT) in 54 patients with active peptic ulcer bleeding or nonbleeding visible vessels at the ulcer base. Nineteen patients received octreotide 100 micrograms bolus i.v. followed by 25 micrograms/h i.v. for 3 days. Twenty patients received HPT. Fifteen patients received ranitidine 100 mg i.v. every 12 h. The three groups were matched for sex, age, location of bleeders, endoscopic findings, shock, and initial hemoglobin. Ultimate hemostasis was obtained in 11 (58%) of the octreotide group, 18 (90%) of the heater probe group, and 8 (53%) of the control group (p < 0.05). Volume of blood transfused, number of patients receiving operation, hospital stay, and number of deaths were not statistically significant among the three groups. We conclude that HPT is more effective than octreotide in the arrest of peptic ulcer bleeding.