Oxidative stress results from an imbalance between the production of reactive species that act as oxidants and the cellular antioxidant capacity. High levels of reactive species have been considered to cause damage of cellular macromolecules and to participate in the pathogenesis of many diseases. Oxidative stress plays an especially important role in the development of cervical intraepithelial neoplasia (CIN). Dietary intake of non-enzymatic antioxidants (e.g. alpha lipoic acid) may contribute to systemic defense against oxidative stress. The goal of this master's thesis was to examine the influence of alpha lipoic acid supplementation on total serum antioxidant capacity of CIN1 and CIN2 positive women, and to associate the influence of certain lifestyle and dietary parameters with oxidative stress prevalence and efficiency of alpha lipoic acid supplementation in this specific group of patients. In this research, antioxidant potential of the serum has been determined by modified TEAC method. It has been shown that body mass index (BMI), cigarette smoking and intake of antioxidant dietary suplements doesn't have an important influence on serum antioxidant capacity of the research subjects. On the other hand, average intake of 3 or more fruit and vegetable portions per day has been associated with significant increase of serum antioxidant potential. Supplementation with 600 mg/day alpha lipoic acid for 90 days has not shown a significant effect on serum antioxidant potential of CIN1 and CIN2 positive women. This research included relatively small nuber of patients, and the biomarker of antioxidant status that has been used isn't very sensitive, so additional research should be conducted to obtain more relevant results and a better insight in alpha lipoic acid's antoxidant ability.