The secretory and motor function of the stomach and gastrin incretion were investigated in 68 patients with peptic ulcer of variable localization. In addition, a retrospective analysis of the course of prepyloric gastric ulcer and Billroth I resection was performed in 62 patients. Results show that gastric acid secretion and velocity of gastric emptying diminish significantly with increasing height of the localization of the ulcer. Prepyloric gastric ulcer cannot be likened to the duodenal ulcer. Moreover, experimental and clinical results suggest that prepyloric ulcer represents a disease entity per se requiring separate therapeutic approaches (gastric resection following Billroth I).