The mechanism by which the mean blood clearance (CLtot,B) of indocyanine green (ICG) was reduced in cirrhotic patients was examined pharmacokinetically. It was demonstrated that the reduction in the CLtot,B of ICG in cirrhosis would be mainly due to the decrease in the hepatic uptake clearance and partly due to the increase in the efflux clearance from the liver to plasma. It is suggested that the decrease in the hepatic uptake clearance in cirrhosis mainly reflects the decrease in the intrinsic clearance of hepatic uptake rather than the decrease in hepatic blood flow.