The efficacy of a combination of ranitidine and pirenzepine in the short-term treatment of duodenal ulcer was evaluated in a double-blind trial. In a multicentre study, 352 patients with active duodenal ulcers were randomly allocated to be treated with 300 mg/day ranitidine plus placebo (group I), 300 mg/day ranitidine plus 50 mg/day pirenzepine (group II), or 300 mg/day ranitidine plus 100 mg/day pirenzepine (group III) for 4 weeks. The respective healing rates assessed using endoscopic examination after 2 and 4 weeks' treatment were 40% and 70% in group 1, 44% and 82% in group II, and 37% and 77% in group III. The differences between the treatment groups were not significant, although 300 mg/day ranitidine plus 50 mg/day pirenzepine tended to be superior to the other treatments. Analgesic activity was the same in the three groups with 33%, 34% and 33% reductions, respectively, in the numbers of patients experiencing pain after 2 weeks. Side-effects (mainly dry mouth and blurred vision) were significantly more frequent in group III patients.