The SARS-CoV-2 outbreak, which caused countless deaths and infections in 216 countries, has become the biggest pandemic of last 100 years [1]. Moreover, the absence of any permanent medicine protocol caused medical, social and economic problems worldwide. The rapid spread of the virus has required doctors to urgently develop treatment using all known drugs. Doxycycline (DOX), a tetracycline antibiotic originally used only in veterinary medicine, was found to be effective against COVID-19 [2]. Due to the high consumption of DOX and other anti-covid drugs, they have penetrated surface waters with human and animal excreta, from industrial wastewater, from human waste, due to improper disposal of expired drugs in the garbage chute or sewerage, from pharmaceutical industries producing antibiotics. This is why it is very important to solve the problem of deep DOX oxidation by applying advanced oxidation processes (AOPs). Among the AOPs, there are used UV, UV/H2O2 systems and the last one represents a cyclic process with OH• radicals generation. The application of these systems is promising for solving the problem of wastewater treatment in the pharmaceutical industry [3-4]. In this work there was studied the kinetics of DOX oxidation under UV irradiation and by the UV-H2O2 system using the spectrophotometric method. Antibiotic concentrations varied between (1,69 -5,625) 10-5 mol/L. For the DOX degradation in the UV-DOX system the mercury-deuterium high-pressure lamp “DRT-100” was used. The degree of degradation at different concentrations of the drug was only 9.1 -11.4%. The conditions of DOX decomposition in the UV/H2O2 system were studied and optimal degradation conditions were identified: [H2O2] = 0.005-0.02 mol/L; [DOX] = (1.697.75)10-5 mol/L; pH = 4,8; T = 298 K; t = 30 - 40 min; λ = 275 nm. The degree of DOX degradation in UV/H2O2 system is 85.58%, which is 74.18% more than in the previous system. It was found that in both systems the decomposition kinetics corresponded to the pseudo-first model with rate constants varying in the range 0.0289-0.0685 min-1. By the method of competing acceptors, the rate constant of the interaction between OH• radicals with the drug used was determined: kOH+DOX = 7.2109 L/mols.