The aim of this study was to investigate the effect of preemptive pantoprazole infusion on early endoscopic findings in patients with acute ulcer bleeding. Records of 333 patients admitted with acute ulcer bleeding were analyzed. Ulcer bleeders were given either 80 mg bolus of pantoprazole followed by continuous infusion of 8 mg per hour or saline infusion until endoscopy. In 93 patients saline infusion whereas in 240 patients bolus plus infusion of pantoprazole was administrated with mean (±SD) durations of hours and hours, respectively ( ). Actively bleeding ulcers were detected in 46/240 (19.2%) of cases in the pantoprazole group as compared with 23/93 (24.7%) in the saline infusion group ( ). Different durations of pantoprazole infusion (0–4 hours, 4 hours, and 6 hours) had no significant effect on endoscopic and clinical outcome parameters in duodenal ulcer bleeders. Gastric ulcer bleeders on pantoprazole infusion longer than 4 and 6 hours before endoscopy had actively bleeding ulcers in 4.3% and 5% compared to the 19.5% active bleeding rate in the saline group ( and ). Preemptive infusion of high-dose pantoprazole longer than 4 hours before endoscopy decreased the ratio of active bleeding only in gastric but not in duodenal ulcer patients.