SUMMARYThe efficacy and safety of famotidine and ranitidine in the treatment of active duodenal ulcer were compared in a multicentre, randomized, double‐blind study. The study was carried out in five centres which included a total of 143 patients with endoscopically documented active duodenal ulcer. The patients received either famotidine (one tablet of 40 mg at night) or ranitidine (two tablets of 150 mg at night). Endoscopic examinations were performed at 4 and 6 weeks of active treatment. Daytime and nocturnal pain were also monitored, and the laboratory and clinical profiles evaluated. One hundred and thirty‐three patients fulfilled the evaluation criteria (66 patients in the famotidine group and 67 in the ranitidine group). Healing rates at 4 or 6 weeks of treatment showed no significant differences between the famotidine and ranitidine groups. The healing rates were 80% at week 4 and 97% at week 6 in the famotidine group, and 77% at week 4 and 96% at week 6 in the ranitidine group. Similar results were observed in both treatment groups with regard to pain resolution, decrease in antacid intake and safety prof