Cholestasis leads to retention of bile salts and other potentially toxic constituents of bile not only systemically but particularly in hepatocytes. This promotes hepatocellular damage and, in a chronic state, can induce the development of fibrosis and cirrhosis of the liver. As recently summarized by Paumgartner and Pusl [225] , the general biochemical and physiologic principles in treating cholestatic liver disease can be broken down to "(1) reduction of hepatocellular uptake of bile salts and other organic anions;