To elucidate the effect of portal congestion on pulmonary interstitial edema after temporary hepatic ischemia by Pringle's maneuver, extravascular lung water (EVLW) was experimentally measured using a modified double indicator dilution method before and after interruption of the hepatic blood flow follwing clamping of the superior meaenteric artery or portofemoral vein bypass. The following results were obtained. 1) Compred with clamping of the superior mesenteric artery, the portofemoral vein bypass reduced the increase of EVLW after temporay hepatic ischemia by Pringle's maneuver. 2) The increase in EVLW had a tendency to be influenced by the degree of metabolic acidosis and portal congestion. These findngs suggest that the portofemoral vein bypass is more effective in the prolongation of the safe period of temporary hepatic ischemia by Pringle's maneuver than clamping of the superior mesenteric artery.