Oxidizing composition to treat keratinous matters, such as human hair, comprises an oxidizing agent (I), oxygenated non-coloring organic compound (II) (at least 30 wt.%) that is insoluble in water and water (20 wt.%), in a medium, where the organic compound is polymeric compound e.g. polyamides 6, polyamides 66, polyamides 11, polyesters, polyurethans, polycyanoacrylates, polymethylmethacrylates, polycarbonates, Teflon (RTM: Polytetrafluoroethylene), silicone resins or elastromers or non-polymeric compounds. Independent claims are included for (1) a process for discoloration of human keratinous fibers e.g. hair, comprising applying the composition to the human keratinous fibers to bleach； leaving for some time to obtain discoloration； eliminating the composition by rinsing with water； and washing with shampoo and optionally drying； (2) a process for scouring of human keratinous fiber, particularly in colored hair, comprising applying the composition on the colored human keratinous fibers to scour, leaving for some time to obtain scouring, eliminating the composition by rinsing with water and washing with shampoo and optionally drying； (3) a process for oxidation dyeing of human keratinous fibers, particularly hair, comprising applying a coloring composition comprising precursor of oxidation dye and an oxidizing composition, on the fibers in a support, where the oxidizing composition is applied either before or after the application of the coloring composition or in mixture with the coloring composition； leaving for 1-60 minutes, preferably 40 minutes； rinsing； washing with shampoo； again rinsing and finally drying； (4) a process for clearing up direct coloring of human keratinous fibers, particularly hair, comprising applying a coloring composition comprising a direct dye and an oxidizing composition, where the oxidizing composition is applied either before or after the application of the coloring composition or in mixture with the coloring composition, on the fiber
