The basis of many chronic diseases is oxidative stress; that is, a state of imbalance between the creation of free radicals (oxidants) and the body's antioxidant defense, in favor of oxidants. Therefore, optimizing the intake of antioxidans is crucial in the context of prevention and/or treatment of oxidative stress-related diseases. α-lipoic acid (ALA) is a powerful antioxidant due to its multiple biological roles (neutralization of free radicals, regeneration of endogenous antioxidants, repair of oxidized damage, metal chelation, etc.) and adequate distribution in the body. The aim of this thesis was to examine the influence of supplementation with α-lipoic acid on the total antioxidant potential in the serum of patients diagnosed with cervical intraepithelial neuroplasia. The research was conducted as a double-blind placebo-controlled study in which patients were supplemented with 600 mg of ALA daily for a period of 3 months. Using the modified ORAC method, the antioxidant potential of serum was measured and the influence of certain parameters of the lifestyle and eating habits of the patients was compared. It was observed that the intake of fruits and vegetables (3 or more portions per day) significantly increased the antioxidant potential of female patients. On the contrary, no difference was observed in the antioxidant potential of female patients related to smoking and body mass index. Supplementation with α-lipoic acid did not significantly affect the ORAC serum values. The effectiveness of ALA in the prevention of oxidative stress has not been properly investigated and the number of available studies is limited. Therefore, further research is needed in order to get better insight into antioxidant efficiency of ALA.