H2-receptor antagonists administered in conventional dosage regimens fail to heal a significant proportion of patients with moderate or severe reflux oesophagitis. We have compared the effects of a higher dose of ranitidine (300 mg q.d.s.) with the currently recommended dosage regimen (150 mg b.d.) in 138 patients suffering from reflux oesophagitis. After 4 weeks of treatment 29% of patients who received 150 mg ranitidine b.d., and 63% of patients who received 300 mg ranitidine q.d.s. had complete endoscopic healing of their lesions (P less than 0.0001). After 8 weeks these proportions had increased to 54% and 75%, respectively (P less than 0.01). After 4 weeks of treatment, compete symptomatic relief had been achieved in 46% of patients who received 150 mg ranitidine b.d. and in 67% of patients who received 300 mg ranitidine q.d.s. (P less than 0.05). After 8 weeks these proportions were 64% and 84%, respectively (P less than 0.05). Both dosage schedules were well-tolerated. We conclude that more rapid symptom relief and healing in reflux oesophagitis can be achieved with 300 mg ranitidine q.d.s. than with 150 mg ranitidine b.d.