Pancreaticogastrostomy has been reintroduced as a useful alternative procedure to pancreaticojejunostomy after Whipple resection or pylorus-preserving pancreaticoduodenectomy because of the very low incidence of leakage and disruption. In this study, gastric acid secretion, serum gastrin level, and 24-hr dual gastroduodenal pH after pancreaticogastrostomy were examined on the assumption that a canine model was a pylorus-preserving pancreaticoduodenectomy. Basal acid output (BAO), maximal acid output (MAO), and dual gastroduodenal pH were measured in eight dogs with gastric fistula. After pancreaticogastrostomy, BAO levels showed a slight increase significantly, but MAO levels showed no change. Serum gastrin levels in the fasting and postprandial states showed the similar patterns between before and after surgery. In the 24-hr dual gastroduodenal pH monitoring, gastric pH and duodenal pH also did not change in the fasting and postprandial states. These results suggested that the maintenance of the normal gastric pH after pancreaticogastrostomy was caused by a little increase of BAO, and the neurohumoral relationship between the stomach, duodenum, and pancreas was preserved even after pancreaticogastrostomy. Therefore, the pancreaticogastrostomy is a recommendable reconstructive procedure physiologically after pylorus-preserving pancreaticoduodenectomy.