Abstract: The invention provides a method for precisely predicting the metabolism of a drug in human liver and the effect of the drug on liver function. The invention provides a method for predicting a metabolite of a test substance produced in human liver and functions of the liver, wherein the method includes administering a test substance to a nonhuman chimeric animal and a non-chimeric animal of the same species, wherein the chimeric animal intracorporeally carries a population of human-origin hepatocytes having proliferation potential and in which the hepatocyte, population substantially functions as the liver of the chimeric animal, and wherein these animals are protected from the attack by a human complement produced by the hepatocytes; and analyzing and comparing metabolites from the chimeric animal and the non-chimeric animal.