A 72-year-old female gave a history of chronic gastrointestinal blood loss necessitating transfusion with over 90 units of blood despite continuous oral iron therapy over a period of 24 years. Gastroscopic appearances were very similar to those recently described by Lewis and by Wheeler in patients with submucosal angiomatous lesions and chronic gastrointestinal blood loss. Striking erythematous streaks radiated from the pylorus and were confined to the antrum. In our case complete achlorhydria to pentagastrin was associated with low serum and antral gastrin concentrations. The introduction of oral prednisolone was followed by a marked fall in the rate of gastrointestinal blood loss, removing the need for transfusion during the following year. Complete achlorhydria persisted and endoscopic appearances remained unchanged, but there was a marked rise in antral and serum gastrin concentrations. The possible modes of action of prednisolone in this case are discussed. The patient remains well in November 1979. The dose of prednisolone was reduced to 10 mg on alternate days in May 1979. Iron supplements have been continued but no transfusion has been required since the start of steroid therapy. The hemoglobin has gradually risen to 14.9 g/dl.