The liquid antacid Novaluzid (10 ml seven times daily) was compared with ranitidine (150 mg twice daily) and with placebo in 57 patients with symptoms and endoscopic signs of oesophagitis and gastro-oesophageal reflux. A randomized three-period change-over design with the double-dummy technique was used. Each treatment period lasted 6 weeks. Only 37 patients (64.9%) completed the entire trial. In retrospect, five patients receiving placebo were withdrawn because of insufficient effect, six patients because of side effects while taking Novaluzid and two while taking ranitidine. The remaining seven dropouts/withdrawals were for reasons without evident relationship to the treatment given. Statistical analyses based both on the 37 completers and on the 43 patients who had at least two treatment periods showed that ranitidine and Novaluzid were superior to placebo with regard to pain score (p less than 0.005) but not with regard to regurgitation, dysphagia, histology, and appearance on endoscopy (p greater than 0.05). It was impossible to distinguish statistically between ranitidine and Novaluzid. In conclusion, ranitidine and high-dose antacids are of equal effectiveness in the short-term treatment of reflux oesophagitis, and both are superior to placebo with regard to symptomatic relief.