The aim of the present study was to evaluate the potential of Turkish propolis extracts if they prevent or protect foreskin fibroblast cells against hydrogen peroxide (H2O2)-induced oxidative DNA damage. Hydrogen peroxide (40 mu M) was used as an inducer of oxidative DNA damage. The damage of DNA was evaluated by using the alkaline single cell gel electrophoresis (comet) assay. Turkish propolis extracts at concentrations of 25, 50, 75 and 100 mu g/ml were prepared by ethanol. Anti-genotoxicity was assessed before, simultaneously, and after treatment of propolis extract (50 mu g/ml) with H2O2. The results showed a significant decrease in H2O2-induced DNA damage in cultures treated with propolis extract. The antioxidant activity of phenolic components found in propolis may contribute to reduce the DNA damage induced by H2O2. Our findings confirmed the chemopreventive activity of propolis and showed that this effect may occur under different mechanisms.