Oxidative stress is defined as imbalance between the production and destruction of reactive oxygen species. The aim of this study was to investigate whether resveratrol could protect human endothelial cells against hydrogen peroxide damage in vitro. In this in vitro study on human coronary endothelial cells, the effects of resveratrol on the glutathione content in human coronary endothelial cells in vitro were evaluated with high performance liquid chromatography. The effects of resveratrol on protein expression of the glutamate cysteine ligase, glutathione peroxidase and glutathione reductase enzymes were evaluated with the Western blot method. Resveratrol increased the reduced glutathione contents significantly (p<0.05). Resveratrol increased protein expression of the glutamate cysteine ligase, glutathione peroxidase-1 and glutathione reductase enzymes (p<0.05). All data supported each other and suggested that resveratrol had a protective effect against human coronary artery endothelial cell damage. It is thought that these results could pave the way to the new therapeutic approaches to protect against oxidative stress that develops in cardiovascular diseases.