Sixty consecutive patients with gastric ulcer were studied at random after treatment with 100 mg pepstatin or 100 mg placebo seven times a day at fixed hours and controlled 2, 4, 8, and 12 weeks after initial diagnosis. Examinations comprised clinical symptoms and endoscopic evaluation of ulcer healing. Eight patients were withdrawn from the study. Ulcer healing and symptoms were better with placebo than with pepstatin, but a type-2 error of a 10% effect in favour of pepstatin may be overlooked. In gastric ulcer treatment, pepstatin seems to be of only fringe benefit, if of any benefit at all.