Concern has been expressed about the possible untoward effect of oral contraceptives on the liver. During the past 10 yr an increasing number of cases of hepatic adenomas and related lesions has been reported in women using oral contraceptives. Such lesions occur only rarely, but it is the rarity itself that makes it difficult to evaluate the role of the contraceptive steroids. The enormity of the denominator in contraceptive steroid usage is so unwieldy that mechanisms to measure accurately the difference in an extremely small numerator are still plaguing the epidemiologist, who at best can supply only estimates. The data to date support an exceedingly low incidence of disease. This is much below the greater risks faced in accepted activities of daily living, particularly as affected by pregnancy itself. A plea is made to develop programs for better prospective evaluations of newer medications along with better animal experimental models.