Daytime reduction of gastro-oesophageal reflux after healing of oesophagitis and its value as an indicator of favourable response to maintenance treatment. In order to investigate the response of gastro-oesophageal reflux after medically induced healing of oesophagitis and its relation to the occurrence of relapse during prophylactic treatment, 20 patients with erosive/ulcerative oesophagitis underwent 24 hour oesophageal pH monitoring before and after healing achieved with 12 to 24 week treatment with ranitidine 150 or 300 mg twice daily. Compared with pretreatment values, after macroscopic healing, a significant reduction in daytime median percentage of reflux time (10.0 v 6.5; p less than 0.05) and median number of reflux episodes lasting more than 5 minutes (5-5 v 1.0; p less than 0.05) were observed, whereas during night time reflux frequency and severity did not change. During maintenance treatment with ranitidine 150 or 300 mg nocte, five of the six patients, who had shown no improvement in gastro-oesophageal reflux after acute healing, relapsed. These results suggest that, in contrast with previous work, a decrease in gastro-oesophageal reflux in patients with reflux oesophagitis can be achieved after macroscopic healing, and that the occurrence of such a reduction after acute healing is predictive of a good response to longterm treatment. 