Ranitidine has been shown to heal the majority of duodenal ulcers during treatment with 300 or 320 mg daily for 4 to 8 weeks. Twice-daily dosage improved compliance. Subsequent maintenance treatment with ranitidinie, 150 mg at night prevented relapse in the majority of patients during 6-months' follow-up. Ranitidine did not appear to have any anti-androgenic effects.