Using conventional manometry and 24-hr ambulatory pressure and pH monitoring, we investigated esophageal motility and the esophageal motor response to reflux in 11 patients with reflux esophagitis Savary-Miller grade III and IV, and an age- and sex-matched group of 11 healthy controls. The patients had a significantly increased esophageal acid exposure. Conventional manometry showed a significantly decreased LES pressure and distal peristaltic amplitude in patients. The 24-hr monitoring yielded a significant decrease in peristaltic contraction duration and peristaltic propagation velocity in the patient group. Distal peristaltic amplitude was not decreased. Analysis of the contractions occurring in the 2-min period after each reflux episode showed a reduced number of contractions during the upright period, caused by a significantly decreased number of peristaltic contractions. During the supine period, there was a trend towards an increased number of contractions. It is concluded that esophageal motor activity and the response to reflux are impaired in patients with high-grade reflux esophagitis. However, the abnormalities found are only minor and are unlikely to play an important role in the pathogenesis of reflux esophagitis.