In this project we have studied the process of oxidation of (+)-catechine on model systems and phenolic compounds of dry red wine “Merlot”, using Fenton’s reagent, with and without inhibitors. The inhibitors of this process used in the study were: quercetin, dihydroxyfumaric acid, sodium dihydroxyfumarate, (+)dimethyl L-tartrare(EDMT), sulfur dioxide. The determinations of (+)-catechine and phenolic compounds concentrations was made with Folin-Ciocâlteu reagent following the described method. We have built up the kinetic diagrams of the (+)-catechine and phenolic compounds consumptions depending on initial concentration of (+)-catechine, Fe2+, H2O2, inhibitors. We have studied the dependence of consumption rate of (+)-catechine and phenolic compounds upon initial concentration of substances listed above and built up a comparative diagram of (+)-catechine and phenolic compounds consumptions, at certain level of inhibitors. Then I put them in the succession of their activity as antioxidant: DFH4<EDMT<Cv<SO2.