HEPATITIS has become an important problem in the practice of medicine during the past two decades. Its incidence is increasing. Originally, attention was focused upon the liver because of damage produced by hepatotoxic agents in therapy, as well as in industry. Of the drugs and chemicals responsible for liver damage, the following may be cited: cinchopen, sulfonamides, bismuth, arsenicals, colloidal gold, quinine, and quinacrine hydrochloride (atabrine® dihydrochloride).1 Among the industrial poisons are carbon tetrachloride, which is outstanding, trinitrotoluene, tetrachloroethylene, and phosphorus. Chloroform and ether are other chemical poisons which may act as toxic irritants on the liver.2 Many infections are capable of producing acute hepatic injury, i. e., virus pneumonia, infectious mononucleosis,3 acute brucellosis, malaria,4 and amebiasis. During World War II a great number of cases of hepatitis appeared in epidemic form, and it was discovered that the etiological factor in many of them wasa virus with a definite incubation