FIELD: cosmetics, polymers, dyes. SUBSTANCE: invention relates to anhydrous compositions for decolorization of keratin fibers, in part, human keratin fibers. Composition comprises at least one alkaline agent and at least one peroxide salt, and at least one water-soluble thickening agent in common with at least non-ionic amphiphilic polymer containing at least one aliphatic chain in medium useful for decolorization and ready for application. Method involves mixing of components with hydrogen peroxide aqueous composition. Invention relates also to method of hair decolorization using these anhydrous compositions and to kit for decolorization of keratin fibers, in part, human keratin fibers. Anhydrous decolorizing compositions comprise thickening system that provides the improved maintenance of viscosity of decolorizing compositions for all time necessary for realization of required decolorization. EFFECT: improved method of decolorization, valuable properties of composition. 24 cl, 2 tbl, 2 ex
