Main pathogenic factors of postvagotomy diarrhea are considered. Among them are: rapid emptying of the stomach due to the draining operation and accelerated passage of chyme along the small intestine, development of a relative insufficiency of digestion and absorption, entrance of the hyperosmolar content into the colon. Diarrhea appears more often after truncal vagotomy, is paroxysmal, then in time regresses and is successfully treated with benzohexamethonium and diet. Surgical correction as the inversion of the segment of the small intestine or restoration of the pyloric sphincter is required in single cases with critical continuously recurring form of diarrhea.