The efficacy of boehmite (Rocgel) and of ranitidine was compared in a randomized, double-blind 4-week trial in patients with symptomatic, endoscopically free macroscopic reflux oesophagitis. Of the 64 patients who completed the study 33 received boehmite and 31 ranitidine. Significant symptomatic improvement occurred in both treatment groups (global clinical score and self evaluation by patients) (p < 0.001). Disappearance of heartburn was 52 per cent (15/29) with boehmite and 53 per cent (16/30) with ranitidine. Disappearance of regurgitation was 48 per cent (10/21) with both treatments. 33% of the patients became totally symptom-free. Our results indicate that boehmite seems to be at least as effective as ranitidine in relieving symptoms. Cost of treatment with boehmite, on the other hand is cheaper than ranitidine. As a safe, locally active mucosal protecting agent and antacid, boehmite is an effective drug for the treatment of reflux oesophagitis without macroscopic lesions.