The antiradical activity of extractive gallotannins isolated from the leaves of the common smoke tree (Cotinus coggygria Scop.), as well as their synergistic eff ects in binary mixtures with low-molecular-weight phenolic acids and their methoxy derivatives have been investigated. The antiradical activity of the compounds has been evaluated by the initial rate of reaction with 2,2’-diphenyl-1-picrylhydrazyl in dimethyl sulfoxide at 298±2 K using photocolorimetry. Extractive gallotannins exhibits higher antiradical activity than a model hydrolysable tannin – decagalloyl glucose. Gallotannins of leaves have shown a versatile capacity for superadditive effects and can form antiradical synergistic systems with natural low-molecular-weight phenolic acids and their methoxy derivatives, enhancing either their own antiradical activity or the activity of the acids. An explicit synergistic effect has been recorded in binary compositions of extractive tannins with phenolic acids in a ratio 7:3 at a total mixture concentration of 3,23·10-2 g·l-1. Its magnitude for combinations with 3,4,5-trimethoxybenzoic and 3,5-dimethoxybenzoic acids was 37,6% and 38,3%, respectively. Using UV spectroscopy, it has been shown that the possible reason for the established synergistic effect is the formation of intermolecular hydrogen-bonded complexes between the components of the system, which reacts with the radical faster than the individual substances. The obtained results allow to recommend binary compositions of extractive gallotannins with methoxy derivatives of phenolic acids as effective low-concentration oxidation inhibitors for lipophilic media and components of combined antioxidant preparations.