**Abstract**

Oxidative stress is the consequence of an imbalance between pro-oxidant and antioxidant processes. Antioxidants that counteract reactive oxygen species do not all work the same way. Both resveratrol and the more powerful 4-hydroxytyrosol are excellent reducing agents. Polyphenol treatment (red wine polyphenols, resveratrol and catechin) is associated with a significant increase in anion permeability for chloride compared with control and 2.2<sup>0</sup> -azobis-2 amidinopropan dihydrochloride affected cells. Treatment with polyphenols was associated with a significant reduction in mean � standard error of the mean membrane lipid peroxidation compared with control and 2.2<sup>0</sup> -azobis-2 amidinopropan dihydrochloride treatment. Hemolysis data are also obtained in the previously described conditions. 4-hydroxytyrosol is shown to significantly protect red blood cells from oxidative damage by 4-hydroxynonenal. But there are paradoxical effects like uric acid and creatinine. The obtained data evidence that both creatinine and uric acid levels have influence on the ratio of both malondialdehyde/protein and 4-hydroxynonenal/protein content on red blood cell ghosts, demonstrating their possible protective role against oxidative stress at low concentrations in blood and oxidizing power at higher concentrations. Finally, polyunsaturated fatty acids do not have all this reducing power.

**Keywords:** reactive oxygen species, resveratrol, 4-hydroxytyrosol, uric acid, creatinine, polyunsaturated fatty acids
