The aim of this double blind trial was to compare omeprazole 20 mg once daily with ranitidine 150 mg b.i.d. in treatment of benign gastric ulcer, evaluating both rates and histological aspects of the ulcer healing process. Eighteen patients were randomized, 9 to each treatment; one patient (ranitidine group) was excluded from the analysis because of malignant ulcer. Omeprazole appeared to be more effective than ranitidine in healing gastric ulcer. A more rapid relief of symptoms was observed in the omeprazole group than in the ranitidine group. Both drugs reduced chronic atrophic gastritis (with a trend in favour of omeprazole), while omeprazole showed a prompter activity on the components of acute inflammation.