The thesis aims to provide evidence supporting the antioxidant efficacy and potential therapeutic effect of chromenone derivatives, in particular, chromone-3-carboxylic acid. The first half of the thesis provides a theoretical overview of the oxidative stress and mechanisms of detoxification, endogenous or exogenous. The latter half of the focuses on the practical experiments conducted by the author. Antioxidant capacity was measured with DPPH and galvinoxyl assays, and the methodology, statistical analysis and the results of the work had been demonstrated and organized. The results of the thesis unequivocally point to the therapeutically relevant free radical scavenging ability of chromone-3-carboxylic acid and its potential use in routine clinical practice.