CAT and cancer: In the in vitro study, it was demonstrated that ascorbate cytotoxicity towards cancer cells is increased synergistically by the concomitant administration of 3-amino-1,2,4-triazole (ATA) which specifically inhibits catalase activity in cancer cells (catalase catalyzes decomposition of hydrogen peroxide H2O2 to oxygen and water), thereby decreasing the ability of cancer cells to detoxify the H2O2 effectively.