Epidemiological studies indicate an increased cardiovascular risk in users of combined oral contraceptives (COC) but not progestagen-only preparations. A specially high risk was observed in women older than 35 years with additional cardiovascular risk factors like smoking or hypertension. The mechanisms underlying arterial occlusion can not be explained by hormonal effects on the vascular tonus, nor by effects on newer risk parameters like homocysteine or transforming growth factor-beta. However, CRP increases during oral and transdermal COC use, an effect which can not be observed during use of a progestagen-only implant. Studies concerning the effect of COC on the vasotonus, nitric oxide, homocysteine and CRP usually include young healthy women with intact endothelial function. Females with nicotinabusus, hypertension and hypercholesterolemia have a damaged endothelium. The effect of hormonal treatment on the endothelium in these women might include decreased ability to release the strong vasodilator nitric oxid and as a consequence of that impaired vasodilation.