The six requirements for a satisfactory animal model of fulminant hepatic failure are reversibility, reproducibility, death from liver failure, a therapeutic window, a large animal model, and minimal hazard to personnel. Different models may be required to evaluate the various types of liver failure seen in man. The available models include surgical anheptic and devascularization procedures, as well as hepatotoxic drug administration using agents such as carbon tetrachloride, acetaminophen, or galactosamine. Currently combined surgical and drug models appear to provide the best model but the search for the ideal models continues.