BACKGROUND: Plasma total homocysteine (p-tHcy) is considered to be an independent risk factor for atherosclerotic vascular disease. This cross-sectional study was undertaken to examine p-tHcy levels and their relationship to coronary artery disease (CAD) and alcohol intake. METHODS: We consecutively studied 291 patients referred for elective coronary angiography due to suspected CAD. The patients completed an alcohol questionnaire, and blood samples were drawn after an overnight fast for measurement of p-tHcy. RESULTS: Patients without CAD (n=85) had significantly lower p-tHcy (10.1+/-4.7 μmol/l) than patients with at least one significant coronary artery stenosis (n=206, p-tHcy: 11.9+/-6.4 μmol/l). Patients with a previous myocardial infarction (MI; n=74) also had a higher p-tHcy (12.3+/-4.0 μmol/l) than patients without MI (n=217; p-tHcy: 10.7+/-6.2 μmol/l). Patients with a daily intake of wine (n=30) had lower p-tHcy (9.4+/-2.8 μmol/l) than patients who did not drink wine (n=47; p-tHcy: 12.1+/-6.0 μmol/l; P<0.05), independent of age, prior MI, and degree of CAD. CONCLUSIONS: p-tHcy correlated positively with CAD. There was an inverse correlation between p-tHcy and wine consumption, suggesting a new potential mechanism by which wine consumption may lower the risk of CAD.