We tested the effects of various antioxidants on H2O2- induced TRPM2 cation channel currents. CHO cells were transfected with cDNA coding for TRPM2. The antioxidants glutathione, vitamins C and E were applied either extracellularly or intracellularly. Non-selective cation currents in whole cell experiments were consistently induced by intracellular ADP- ribose, NAD and extracellular H2O2. ADP-ribose and NAD was characterized a slow current induction to a plateau although the inward currents of H2O2 administration did not reach a plateau after even 15-20 min. No intracellular antioxidants prevented the H2O2- induced current development in whole and single-channel activities of the cells. We concluded that non reversible the selective cation channel currents induced by H2O2 although the antioxidants have no effects on the activation.