Tumorous lesions of the liver were diagnosed by means of angiography, sonography and laparoscopy in six patients on oral contraceptives for a long time. These lesions were identified as liver cell adenoma (1), focal nodular hyperplasia (4) and cavernous hemangioma (1). The relationship between oral contraceptives and liver disorders is well-known. All cases of focal nodular hyperplasia show vascular alterations which may be important in the discussion of oral contraceptives being responsible. In contrast to liver cell adenoma and hemangioma, focal nodular hyperplasia may be considered as a nodular reparative regeneration of the parenchyma following focal parenchymal necrosis due to segmental vascular occlusion (i. e. thrombosis or fibrotic intimal obliteration). This lesions can therefore not be defined as a true neoplasm. The clinical findings are uncharacteristic, whereas selective hepatic artery angiography, shows typical features that distinguish liver cell adenoma from focal nodular hyperplasia. Regular medical examinations are recommended for women on continuous oral contraceptives for more than five years, because this group of patients is threatened by serious sequelae including intrahepatic and abdominal hemorrhage.