Changes of hepatic venous wedge pressure (WHVP) and portal venous pressure (PVP) in fourteen patients with postnecrotic cirrhosis proved pathologically and seven patients with colon carcinoma without hepatopathy were observed before and after the infusion of alpha-adrenergic receptor antagonist phentolamine from peripheral venous. The results indicate that phentolamine can reduce WHVP and PVP of cirrhotic patients with portal hypertension efficiently (0.56-0.63 kPa, 0.42-0.50 kPa, respectively, P < 0.01), but it effects arterial diastolic pressure and heart rate simultaneously (arterial diastolic pressure reduced by 0.94-10.7 kPa, while heart rate increased by 8.67-10.67 per minute). Phentolamine doec not reduce portal pressure on patients without portal hypertension.