To evaluate the understandability and the validity of information included in package inserts of the 20 main oral contraceptive (OC) preparations sold in Italy, we systematically tabulated the indications, contraindications and side-effects listed in their patient information leaflets. OC information leaflets included, in their vast majority, only contraception as indication, with no mention of endometriosis, dysmenorrhea, or other menstrual cycle disorders, which are potential indications for OC use. In contrast, information leaflets included an extremely detailed, but largely acritical, list of contraindications and side-effects, in the absence of any quantitative indication on their frequency and importance. These include, among others, depressive symptoms, visual impairments, or endometrial hyperplasia, which is indeed an indication for combined OC use. Such acritical and poorly explained information on potential, but often unproven, side-effects may cause confusion and lead to withdrawal from OC use for some women, in the absence of any real contraindication. In contrast, some real contraindications or serious side-effects, including cervical neoplasia, hepatomas, liver cancer or myocardial infarction, were not reported in OC leaflets. The incomplete data, and particularly the absence of quantitative information on OC leaflets, may cause negative attitudes of women towards their use, decreased compliance, and, however indirectly, be a determinant of the low prevalence of OC use among Italian women.