Objective: Moderate alcohol consumption has been associated with beneficial effects on coronary heart disease. This positive effect has been partly attributed to the flavonol contents which promote vasodilatory, anti-aggregatory and antioxidative effects and protect low-density lipoprotein (LDL) cholesterol from oxidation. Thus, the present study was carried out to determine the acute effects of different wines on LDL oxidization in healthy volunteers. Methods: Healthy male and female subjects (15/group) on a flavonol-restricted diet were randomly assigned to drink 300 ml wine from one of four different grapes and fermentation processes. Conjugated fatty acid dienes and thiobarbituric acid reactive substances (TBARS) were determined as a measure of LDL oxidation in serum at baseline and up to 96 h after wine ingestion. Results: At baseline, mean conjugated dienes in serum were 12.5 +/- 6.2 mu mol/ l and mean TBARS in serum were 15.7 +/- 8.1 mu mol/ l. There were no differences between the groups and no effect of any wine type on conjugated dienes ( p = 0.15) or TBARS ( p = 0.38) over time. 96 h following wine ingestion, the mean conjugated dienes were 12.1 +/- 4.12 mu mol/l and mean TBARS were 16.4 +/- 8.8 mu mol/l ( pooled data, n = 60). Conclusion: Ingestion of 300 ml wine does not protect LDL from oxidation in vivo in healthy subjects. However, this does not exclude an effect of habitual wine consumption on LDL plasma oxidation. Copyright (C) 2005 S. Karger AG, Basel.