This study was aimed at investigating the effects of propranolol on esophageal variceal pressure in patients with portal hypertension. Variceal pressure was measured at endoscopy using a miniature pressure-sensitive gauge in 20 patients with portal hypertension. Measurements were obtained under baseline conditions and 20 min after double-blind administration of propranolol (0.15 mg/kg; n = 10) or an identical amount of placebo (normal saline, 0.3 ml/kg; n = 10). Under baseline conditions, variceal pressure was similar in propranolol and placebo groups (14.1 +/- 5 mm Hg vs. 14.9 +/- 6.6 mm Hg, respectively; not significant). Placebo had no significant effect on variceal pressure (baseline = 14.9 +/- 6.6 mm Hg; placebo = 15.5 +/- 6.6 mm Hg; not significant), and values after placebo administration were closely correlated with baseline values (r = 0.98; y = 1.1 + 0.97 x; p less than 0.0001). In contrast, propranolol caused a significant decrease in the pressure of esophageal varices (from 14.1 +/- 5 mm Hg to 11.3 +/- 4.4 mm Hg; p less than 0.0002). No significant changes in the size of esophageal varices were observed after propranolol or placebo administration. This study shows (a) the endoscopic pressure-gauge technique has a low variability and may be used to assess acute drug-induced changes in variceal pressure; and (b) propranolol causes significant decreases in variceal pressure in patients with portal hypertension and esophageal varices.