Summary To determine the role of portacaval shunts in the development of hepatic siderosis, rats were subjected to end-to-side and side-to-side portacaval shunts. Hepatic siderosis developed only in rats with end-to-side shunts, while visible liver cell damage and cirrhosis were absent. It is concluded that shunting of the portal blood flow per se results in hepatic siderosis, even in the absence of cirrhosis.