Elevated plasma homocyst(e)ine levels have prothrombotic and proatherosclerotic effects. Data from prospective studies indicated that plasma homocyst(e)ine acts as a modest independent predictor of coronary heart disease. At present, no conclusive data are available on the possible interaction between hyperhomocyst(e)inemia and hypertension and the occurrence of cardiovascular events. Recent longitudinal studies in high risk patients indicated that hyperhomocyst(e)inemia is strongly associated with recurrent cardiovascular events. However, this finding is not in line with the few available data from prospective studies, which failed to observe a protective role of homocyst(e)ine-lowering therapy in secondary prevention of cardiovascular events. Future results from ongoing larger trials are expected to provide more definitive answers concerning the need to support the routine use of folic acid in patients with CHD. Since the definitive impact of mild hyperhomocyst(e)inemia on coronary heart disease is still to be established, widespread determination of homocyst(e)ine levels is not needed in a general population at the present time. In contrast, knowledge of homocyst(e)inemia may be important for specific groups of individuals, such as high risk patients, and for those patients in whom traditional risk factors do not appear to account for an increased incidence of cardiovascular events.