Thirteen patients with pancreaticoduodenectomy were studied. In three patients presenting with stomal ulcer or bleeding stomitis, endoscopic biopsies showed the presence of retained antral mucosa (RAM). No disease and no RAM was present in the remaining ten patients. Bombesin (BBS) infusion augmented both gastric acid and gastrin secretion in the group with RAM, whereas no change was apparent in the remaining ten patients. The BBS infusion test is useful in detecting stomal ulcer high risk pancreaticoduodenectomy patients.