Previous work from this laboratory1 established that massive small bowel resection, or intestinal bypass, produces a striking increase in the secretion of acid from Heidenhain pouches in dogs. This observation has been confirmed and extended by similar, though not identical, experiments in other laboratories.2-7 Although previous attempts have been made to clarify the possible role of the gastric antrum in this postenterectomy hypersecretion, the issue has not been settled. The present study was undertaken to determine if postenterectomy hypersecretion occurs in the absence of the antrum. Method Eight mongrel dogs of both sexes, varying in weight between 12.2 and 18.4 kg were used. Operations were performed aseptically under pentobarbital sodium anesthesia. The animals were maintained on a standard kennel ration and were provided a measured amount of food at the same time each day. Food pans remained in the cages for one hour only and the residual food,