Our study of more than 250 women with hepatic tumors, accessioned in our tumor registry at the University of Louisville, disclosed three types of tumor: FNH , HCA, and HCC. The ingestion of sundry kinds of sex steroids by the majority of these women, chiefly for purposes of preventing conception, warrants the suspicion that such hormones induced these different types of hepatic tumors. Publications by others reporting similar hepatic tumors in men using male sex steroids lends support to this hypothesis. Rupture of the hepatic tumor and consequent hemorrhage, producing hemoperitoneum, is a major risk factor. Other presenting symptoms are pain and palpable mass. Symptomatic women using OCs should be subjected to a CT or technetium hepatic scan as an initial screening assessment. Because of the imminent possibility of rupture, large turgid vascular tumors should be resected without biopsy. Biopsy-proved HCC should also be removed surgically. All other tumors, including small multiple tumors, will usually regress when exogenous sex steroids are withdrawn and pregnancy avoided. Other significant hepatic changes observed in this study are peliosis hepatis, periportal sinusoidal dilation, and vascular lesions. The branches of the hepatic artery and the tributaries of the portal vein show combinations of intimal and smooth muscle proliferation, vascular thickening, occlusive intimal thickening, and, at times, obstructing thrombosis. Similar smooth muscle proliferation in the afferent vessels of the livers of animals treated with sex steroids suggests that there is a cause and effect relationship in women using OCs.