In our study, the effect of simultaneous pretreatment with plasma levels of vitamins C and E on the toxicity of CdCl₂ in human erythrocytes was evaluated. We aimed to examine how several different doses of CdCl₂ or CdCl₂, in combination with vitamins, affects lipid peroxidation and the antioxidant defense system in vitro. Levels of malondialdehyde and the activities of antioxidant enzymes changed in CdCl₂-treated groups in different concentrations. Vitamin-pretreated erythrocytes showed significant protection aganist the cytotoxic effects induced by low and moderate CdCl₂ concentrations on the studied parameters.