In this study, pyloric stenosis appeared to be a commonly occurring, independent, entity probably resulting from antral pyloric canal gastritis rather than from an ulcer crater per se. An appropriate term might be stenosing pyloritis. Intraoperative effects on the pyloric sphincter from glucagon and atropine administration and stimulation of the vagi and gastric pacemaker were not detectable in a limited study on four cases. A local autonomy of sphincteric action was noted which was not affected by trunkal vagotomy.