It is known that moderate red wine consumption can reduce the risk of cardiovascular disease. The protective effects of wine have been attributed to phenolic compounds that are efficient scavengers of free radicals and breakers of lipid peroxidative chain reactions. Besides antioxidant activity, phenols also have anti-inflammatory effects and may protect low-density lipoproteins (LDL) against oxidative modification. The aim of this study was to determine the effects of the so-called "organic" wines (i.e., those that are produced from genetically nonmodified grapes and without fertilization) and "nonorganic" red wines (i.e., those that are produced in a conventional manner) on LDL oxidation, antioxidant activity, and other antioxidant enzymes such as catalase and superoxide dismutase. Male subjects (n = 6) drank 200 mL and female subjects drank (n = 2) 100 mL of red wine (the so-called organic wine) wine, and after 6 weeks the experiment was repeated with the nonorganic red wine. Blood samples were obtained at baseline and after 60 and 360 minutes. Total phenol, erythrocyte superoxide dismutase (e-SOD), erythrocyte catalase (e-CAT), erythrocyte thiobarbituric acid reactive substances (eTBARS), serum total antioxidant activity (AOA), LDL-TBARS, and Cu-stimulated LDL-TBARS levels were determined. Although the Cabernet Sauvignon wine caused a significant increase in eSOD activity during hour 1 (P = 0.046) and hour 6 (P = 0.028) of the experiment compared to the baseline levels, it led to an insignificant increase in eCAT activity in hour 1 (P = 0.08) and hour 6 (P = 0.069). There was no significant difference between two types of wines with respect to LDL-TBARS blood levels, and only the nonorganic wine led to a decrease in Cu-stimulated LDL-TBARS. There were noteworthy differences in the alcohol and phenol content of the organic and nonorganic wines. (C) 2004 Elsevier Inc. All rights reserved.