1. Establishing the cause of fulminant hepatitis is an important step in the management of acute liver failure, so that specific therapy can be initiated and any contraindications to liver transplantation can be eliminated. 2. The etiology of fulminant hepatitis varies in different countries and at different times. A viral etiology (in particular hepatitis B virus) is now less frequent, and paracetamol-induced fulminant hepatic failure is more common. 3. Many patients have miscellaneous causes of fulminant hepatitis. It is important to establish the main clinical and biological characteristics for specific management. 4. Assessment of the prognosis of fulminant hepatitis is important for distinguishing patients requiring liver transplantation from those whose will improve spontaneously. Prognosis depends on several factors, including the gold standard, the King's College Hospital criteria and Clichy's criteria.