Lower esophageal sphincter pressure (LESP) was studied by intraluminal perfusion-manometry in the resting state and after graded intravenous doses of pentagastrin in 12 healthy subjects and 27 patients with reflux esophagitis. These patients were classified as having ulcerative (11) or non-ulcerative esophagitis (16) by histological examination and endoscopic appearance of the inflamed mucosa. The length of the LES was similar in patients and controls. A correlation was found between the magnitude of mean basal end-expiratory (mbe) LESP reduction and the grade of esophageal mucosa inflammation. The most reduced mbe LESP value was shown in patients with ulcerative esophagitis. It was significantly different from that of patients with non-ulcerative esophagitis (t = 3.37, p less than 0.01). Both values were significantly reduced from that of the controls (t larger than or equal to 0.0125). The responsiveness of the LES to intravenous pentagastrin was quantitatively reduced throughout the whole range of the dose-response curve in patients with ulcerative esophagitis, whereas patients with non-ulcerative esophagitis only differed in the maximum mbe pressure value from the controls. Four patients showed a paradoxical pressure decrease to intravenous pentagastrin, resulting in a LESP reduction to 8% of the mbe LESP. Intravenous secretin or CCK led to a similar reaction of the LES in these patients.