One hundred consecutive patients with non-ulcer dyspepsia (NUD) and the endoscopic diagnosis of erosive prepyloric changes (EPC) were included in a 4-week double-blind, placebo-controlled trial. The patients were randomly allocated to treatment with either Al-Mg antacids (one tablet four times daily; acid-neutralizing capacity, 120 mmol/day) or antacid placebo, in combination with either pirenzepine (50 mg twice daily) or pirenzepine placebo. Ninety patients completed the study. Symptoms improved during the 4 weeks in all treatment groups, irrespective of the treatment given. Neither pirenzepine nor antacid was significantly superior to placebo. Re-endoscopy after 4 weeks of treatment showed no significant change in the EPC grade. No serious side effects were observed, but xerostomia occurred more frequently in patients treated with pirenzepine than in those treated with placebo (p less than 0.01).