The phenomenon of catalysis of the heterolytic decomposition of alpha-phenylatyl hydroperoxide by additions of an anionic surface-active substance - sodium dodecylsulphate - has been established. The activation energy of this process E-eff = 66.3 kJ/mole. Autosynergism was found, and the inhibiting action of sodium dodecylsulphate in alkylaromatic hydrocarbons was revealed. Additions of sodium dodecylsulphate by non-radical means break down hydroperoxides with the formation of phenol, which consequently leads to the appearance in the system of an antioxidant of complex action - an acceptor of peroxide radicals and a non-radical agent breaking down the hydroperoxide. The mechanism proposed is confirmed by data from analysing the reaction products and the kinetics of the process.