Abstract
Distal esophageal pH was monitored for 3 h after a standard meal in 10 young, healthy subjects without symptoms of gastro-esophageal reflux. Episodes of reflux occurred in 9 of these subjects. In 5, esophageal pH was < 5 for between 11-75% of the 1st postprandial hour. Intermittent incompetence of the lower esophageal sphincter after food must be regarded as a normal phenomenon. The method described would be suitable for the evaluation of agents believed to weaken or to strengthen the lower esophageal sphincter.