Background: 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 oesophagitis.