The aim of this study was to follow up whether the modification of pro-antioxidant status by oral thiol administration such as N-acetylcysteine and alpha-lipoic acid affects the hematological response. Twenty-eight healthy men participated in two independent experiments. Subjects were randomly assigned to one of four groups: controls (C(NAC) and C(ALA)), N-acetylcysteine (NAC) and alpha-lipoic acid (ALA). 1200 mg of N-acetylcysteine, 600 mg of alpha-lipoic acid or placebo were administered for 8 days in two doses. NAC or ALA administration significantly elevated plasma total antioxidant status (TAS) and reduced protein carbonylation (PC) and lipid peroxidation (TBARS) by more than 30 %. The reduced glutathione (GSH) and hematological parameters changed only in response to NAC administration. NAC significantly elevated the level of GSH (+33%), EPO (+26%), Hb (+9%) and Hct (+9%) compared with C(NAC). The mean corpuscular volume (MCV) and the mean corpuscular hemoglobin (MCH) also increased by more than 12% after NAC. The numerous negative or positive correlations between the measures of TAS, PC, TBARS and hematological parameters were found, which suggest the NAC-induced interaction between pro-antioxidant and hematological values. Our study has shown that both N-acetylcysteine and alpha-lipoic acid intake reveal an antioxidant action, but only N-acetylcysteine improves the haematological response.