In 70 consecutive patients with symptoms of gastroesophageal reflux (GER), we studied lower esophageal sphincter (LES) and upper esophageal sphincter (UES) pressures, esophageal peristalsis, and esophageal acid exposure 5 and 20 cm above the LES. Based on the percentage of time the pH was below 4 in the proximal esophagus, the patients were divided into 2 groups: (1) group A, less than 3%, 48 patients; (2) group B, greater than 3%, 22 patients. LES was weaker (13.5 +/- 6.0 mm Hg in group A versus 7.8 +/- 4.6 mm Hg in group B) and shorter (2.2 +/- 0.7 cm in group A versus 1.5 +/- 0.5 cm in group B) in group B patients. Group B patients also had lower amplitude of peristalsis in the proximal (59.2 +/- 17.6 mm Hg in group A versus 42.4 +/- 18 mm Hg in group B) and distal esophagus (89.7 +/- 25.2 mm Hg in group A versus 54.7 +/- 27.9 mm Hg in group B) and lower UES pressures (73.7 +/- 30.7 mm Hg in group A versus 54.7 +/- 29.3 mm Hg in group B). Forty-one percent of group B patients had pulmonary aspiration, whereas only 2% of the patients in group A experienced pulmonary aspiration. These data show that, in a subgroup of patients with symptoms of GER, the upper esophagus is exposed to acid for more than 3% of the time. Patients with high GER differ clinically and pathophysiologically from those in whom reflux is limited to the distal part of the esophagus: those with high GER have a panesophageal motor dysfunction and a high risk of aspiration.