Two cases are described, which revealed the picture of a dihydralazine-induced chronic aggressive hepatitis bioptically. One case was laparotomized under the clinical diagnosis of obstruction jaundice, the other exhibited no symptoms and was detected by elevated transaminases only. The time of exposure was 2-3 years. After withdrawal of dihydralazine the patients recovered within 2-3 months. Elevated transaminases (more than 1 mumol) should given occasion for withdrawing the drug or for performing of liver biopsy. In a total of 6,581 liver biopsies within five years an acute dihydralazine-hepatitis was seen more frequent than a chronic one (ratio 77:2).