A HIGH incidence of jejunal ulcer after pancreaticoduodenectomy has been reported.1 The factors responsible for this have not been defined. Among the possible causes are (1) impingement of acid-peptic secretion on anatomosed jejunum with low resistance to ulceration, (2) unusually high secretory activity of the gastric remnant, (3) reduction or absence of pancreatic secretion secondary to pancreatic resection or pancreatic duct obstruction, and (4) ulcerogenic anastomotic arrangement with diversion of bile and pancreatic secretion away from the gastrojejunostomy. In an attempt to understand this problem better, gastric secretion tests have been carried out on 14 patients after pancreaticoduodenectomy. The results of these secretory tests have been correlated with the presence or absence of ulcers, the type of reconstruction after resection, and the extent of gastric resection. By comparison with similar data on other groups of patients it is possible to place this type of patient in perspective and arrive