SUMMARYBackground: Lansoprazole is a new proton pump inhibitor which produces prolonged decrease of gastric acidity. The aim of this study was to compare lansoprazole to a standard dose of ranitidine in the treatment of patients with reflux oesophagitis.Methods: Two hundred and forty‐seven patients with erosive oesophagitis were randomly assigned to 8 weeks of treatment with either 30 mg lansoprazole once daily or 150 mg ranitidine twice daily.Results: Two hundred and forty‐two patients were included in the analysis. Lansoprazole (30 mg) daily, healed oesophagitis in 92.1% of patients after 8 weeks of treatment. This was significantly superior to 150 mg ranitidine b.d.s. which healed oesophagitis in 69.9% of patients (P<0.001). Relief of reflux symptoms was superior with lansoprazole to that with ranitidine. Both lansoprazole and ranitidine were well tolerated with no serious drug‐related adverse events noted.Conclusion: Lansoprazole, 30 mg once daily, is highly effective and safe in the short‐term treatment of erosive oesop