Flavonoids are ingested with vegetables and beverages and exert a beneficial effect on cardiovascular disease. Studies in animals in vitro and in humans ex vivo on the resistance of lipoproteins to oxidation are not consistent and the mechanisms by which flavonoids protect against atherosclerosis are a matter of debate. In the present study we investigated the effects of administering diets containing 0.3% (w/w) quercetin, 0.3% (w/w) catechin or 35% (v/w) dealcoholated red wine (DRW) for 10 d in rats on markers of oxidative damage in lipoproteins and in plasma. The antioxidant levels in low-density lipoproteins (LDL) or the lag phase, oxidation rate and maximum level of conjugated dienes (CD) during ex vivo LDL oxidation did not differ between control and treated rats. Plasma levels of -tocopherol and retinol were similar in all groups. The total antioxidant status (TAS) of the plasma from rats fed either quercetin or DRW diet was higher than in control rats. Only glucuronide and sulfate compounds of quercetin were detected in plasma from rats fed the quercetin-rich diet, and no flavonoids or their metabolites were detected in plasma or LDL from rats fed the catechin- or the DRW-rich diet. No significant differences in malondialdehyde (MDA) or in CD in plasma were observed. These results indicate that although metabolites from quercetin are present in plasma, they are not detected in lipoproteins and do not modify the level of other antioxidants. In conclusion, in our conditions the intake of quercetin, catechin or DRW were not able to protect lipoproteins from oxidation ex vivo.