The present study investigated to what extent measurements of wedged and free hepatic venous pressures adequately reflect the effects of vasopressin at the esophageal varices in patients with cirrhosis. Eleven patients undergoing therapeutic sclerotherapy were studied by measuring wedged hepatic venous pressure, intravariceal pressure, free hepatic venous pressure, superior vena cava pressure and the intravascular pressure gradients wedged hepatic venous pressure-free hepatic venous pressure and intravariceal pressure-superior vena cava pressure, prior to and after vasopressin injection (1 IU, iv). Vasopressin caused a significant reduction in intravariceal pressure (from 22.5 ± 9.4 to 19.2 ± 8.4 mm Hg, p < 0.001). Measurement of wedged hepatic venous pressure and free hepatic venous pressure closely reflected the reduction in variceal pressure. Thus, wedged hepatic venous pressure decreased by 16 ± 11%, which is close to the 14 ± 7% change in intravariceal pressure, and the 23 ± 12% fall in the pressure gradient wedged hepatic venous pressure-free hepatic venous pressure was mirrored by the 26 ± 10% change in intravariceal pressure-superior vena cava pressure. These pressure gradients decreased more than the absolute pressures (intravariceal pressure and wedged hepatic venous pressure) due to concomitant increases in superior vena cava pressure (1.9 ± 1.9 mm Hg) and free hepatic venous pressure (0.6 ± 1.9 mm Hg). Since variceal wall tension, a parameter influencing the risk and severity of variceal bleeding, is modified by changes in intravariceal pressure but not by changes in superior vena cava pressure, our data suggest that the favorable effect of vasopressin is best indicated by the moderate fall in intravariceal pressure than by the greater reductions in the intravascular pressure gradients. This might explain the somehow deceiving results of vasopressin therapy for variceal hemorrhage. In addition, the study shows that the simple and safe technique of hepatic vein catheterization adequately reflects the effects of vasopressin on variceal pressure.