The gastric secretory status of 75 patients with abnormal esophageal exposure to gastric juice proved by 24-hour pH monitoring was measured to study the significance of gastric hypersecretion in gastroesophageal reflux disease. Gastric hypersecretion was a less-frequent finding than a mechanically defective sphincter (28% vs 72%, respectively). Forty-eight percent of patients with a normal sphincter, compared with 20% of those with a defective sphincter, were hypersecretors. In the presence of normal gastric secretion, complications occurred in 18% of those with a normal sphincter and 77% of those with a defective sphincter. In the presence of hypersecretion, the complication rate was 40% and 82%, respectively. These findings show that the development of reflux complications are related to a defective sphincter. Gastric hypersecretion in reflux patients with a normal sphincter is best treated by acid reduction using H2 blockers. Patients with a mechanically defective sphincter, regardless of their gastric secretory state, should have an antireflux procedure.