We report the cases of four adult patients suffering from acute hepatitis due to isaxonine phosphate (Nerfactor), a drug recently proposed for the treatment of the lesions of peripheral nerves. Hepatitis developed 14 to 166 days after the beginning of the administration of the drug. In all the patients, predominantly centrilobular hepatocytic necrosis was present. In two of our patients, the course of hepatitis was fatal. Hepatitis induced by isaxonine phosphate is likely to be due to an immuno-allergic mechanism.