Eighteen patients with progressive systemic sclerosis and symptomatic gastroesophageal reflux were studied for 20 weeks. All patients were initially treated with ranitidine for a 6-week period. From the 7th week the patients were randomized to further treatment with either ranitidine or placebo. Heartburn and dysphagia, the endoscopic appearance of the esophageal mucosa, the esophageal motility, and gastroesophageal reflux were assessed during the study. The efficacy of ranitidine was maintained during the 20-week period. A shift to placebo was recognized by the patients almost immediately and caused heartburn and esophageal mucosal inflammation to increase significantly.