OBJECTIVE: To compare two regimens of pantoprazole administered intravenously in patients with ulcerative gastrointestinal bleeding (UGB), and a high risk of presenting with persitent or recurrent hemorrhage. MATERIAL AND METHOD: Patients were randomized into two groups: group 0--treatment with a 80 mg bolus of pantoprazole administered intravenously, followed by continuous infusion of 8 mg/h for 72 hours; group 1--treatment with 40 mg of pantoprazole administered intravenously on a daily basis. The percentage of hemorrhagic persistence/recurrence in both groups was analyzed, as were transfusion requirements, need for surgery, and mortality resulting from the hemorrhagic episode. RESULTS: There were 20 patients in group 0 and 21 in group 1. No differences were found between groups in terms of gender, age, smoking habits, use of NSAIDs, presence of hemodynamic instability or stigmata in ulcer crater (Forrest Ia: 5 vs. 14.3%, p = 0.322; Forrest Ib: 30 vs. 33.3%, p = 0.819; Forrest IIa: 60 vs. 50.1%, p = 0.753). In group 0, 90% of patients received endoscopic treatment, versus 100% in group 1, p = 0.232. In group 0, 50% of patients had a transfusion, as compared to 52.4% in group 1, p = 0.879. In group 0, 2 patients (10.5%) presented with recurrent hemorrhage, versus 3 patients (14.3%) in group 1. Surgery was required by 1 person from each group, and 1 patient in group 0 died. CONCLUSIONS: Maximum acid inhibition with a bolus and then a continuous infusion of pantoprazole does not yield better results than treatment with conventional doses in acute hemorrhagic episodes.