Twenty cirrhotic patients with esophageal varices and an episode of gastrointestinal bleeding within the previous week underwent hemodynamic studies which used an indicator dilution technique based on selective catheterization of the splanchnic arteries and hepatic vein. Portasystemic shunting of splenic arterial flow averaged 95% (range 80 to 100%) in 17 patients with proved variceal bleeding, but only 8% in 3 who bled from another site. Superior mesenteric shunting averaged 70% (range 27 to 100%) in those who bled from varices, and no shunting was detectable in the nonvariceal bleeders. In at least 4 patients shunting was essentially complete from both beds. In 11 others, however, more than one-third of mesenteric flow still perfused the liver. The pressure gradient from the wedge to free position in the hepatic vein and the hepatic blood flow bore no relationship to the degree of shunting. These data indicated the variability of the splanchnic hemodynamic pattern that may exist in alcoholic patients with esophageal varices. If hemodynamic factors are important in determining the response to surgery, indicator dilution studies to quantitate portasystemic shunting may be a vital part of preoperative evaluation.