Case reports of 3 patients are given with severe corrosive lesions of the esophagus and stomach due to acid ingestion. All of them survived the initial phase and seemed to be expecting a favourable clinical course. In all of these cases however massive upper gastrointestinal bleeding, perforation, and death occurred in a later phase after an interval free of symptoms. Treatment of severe corrosions of the upper gastrointestinal tract differs significantly from treatment of less serious cases. In less severe cases care has to be taken to avoid later complications in the first place. If there are serious corrosions however vital indications are predominant in determining the course of treatment during the initial phase. An interval with no or rather few clinical symptoms of 3 weeks duration after severe corrosive lesions should not be considered to exclude the danger of later lethal complications, especially bleeding and perforation. In order to avoid such complications endoscopic and eventually surgical exploration after the acute initial phase is recommended.