In a randomised, multicentre trial, nizatidine 150 mg or 300 mg or placebo was administered twice daily for 6 weeks to 515 patients with gastro-oesophageal reflux disease (GORD). Antacid tablets were taken as needed for pain. Significantly superior rates of endoscopically proven complete healing (normal-appearing mucosa) versus placebo occurred after 3 weeks with nizatidine 150 mg and after 6 weeks with nizatidine 300 mg. Six-week healing rates were 38.5% for nizatidine 300 mg, 41.1% for nizatidine 150 mg, and 25.8% for placebo. The nizatidine 150 mg treatment group had significantly greater improvement in daytime and nighttime heartburn severity after 1 day of therapy versus placebo. Twice-daily administration of nizatidine 150 mg or 300 mg provides prompt relief from the major symptom of GORD, heartburn, and complete healing of oesophagitis is seen in many patients.