Polyphenols are of increasing interest to consumers and food manufacturers for several reasons.Phenolic compounds extraction from grape seed extract (GSE) may prevent various oxidative stress-related diseases,such as cancer,cardiovascular disease,inflammation and others.Physical activity is known to induce oxidative stress in individuals after intensive exercise.The present study was to investigate whether grape seed extract supplementation would attenuate antioxidation induced after marathon exercise.Sixteen recreational marathon runners were divided into two groups.