Twenty healthy males were divided into two groups: 10 subjects were supplemented for 2 weeks with 400 ml of red wine (11% alcohol) per day and the other 10 subjects were given 400 ml of white wine (11% alcohol) per day for a similar period. Blood samples were drawn prior to wine supplementation, after 1 week and at the end of the study. No significant effects were found on plasma concentrations of urea, creatinine, bilirubin, creatine kinase, amylase, blood cell counts, platelet counts and platelet aggregation. Both red- and white-wine supplementation resulted in a transient minor reduction in plasma glucose concentration and in a minor elevation in blood coagulation properties such as prothrombin time and partial thromboplastin time. Red (but not white) wine resulted in an 11 and 26% increment in plasma triglyceride concentrations after 1 and 2 weeks of supplementation, respectively. Plasma cholesterol, as well as very-low- and low-density-lipoprotein levels did not change during the 2 weeks of red- or white-wine supplementation. The most impressive effect of red-wine intake was a significant (p < 0.01) increase in plasma high-density lipoprotein (HDL) cholesterol and in plasma apolipoprotein A-I concentrations by up to 26 and 12%, respectively. These effects were not observed after the intake of white wine. We conclude that the major effect of red-wine supplementation (about 40 g of alcohol per day for a period of 2 weeks) was a significant increase in plasma HDL concentration which may contribute to the reduced risk for cardiovascular diseases observed in red-wine drinkers.