A low platelet count is a common finding in liver cirrhosis. Clinical practice has shown that a variable number of cirrhotic patients in whom portasystemic shunting procedures have been performed does not recover from thrombocytopenia: this observation questions the role that portal hypertension may have in maintaining the low platelet count. We have previously described the appearance of thrombocytopenia in rats submitted to portacaval shunt 1 month after the operation. In the present study we have investigated a supposed protective influence of a good liver function in maintaining a normal thrombocytopenia: 56 male Wistar rats were divided into 4 groups: group A (15 rats) sham-operated; group B (16 rats) submitted to portacaval shunt (PCS); group C (17 rats) submitted to PCS plus arterialization of the portal stump by the right renal artery, and group D (8 rats) submitted to PCS plus right nephrectomy. Group B (PCS) and D (PCS plus right nephrectomy) showed a marked thrombocytopenia, whereas group A (sham-operated) and C (PCS plus liver arterialization) evidenced a normal platelet count. These results strongly support the hypothesis that a low platelet count can ensue during a chronic liver disease in the absence of portal hypertension and that restoration of the hepatic blood flow can prevent thrombocytopenia.