Thickened oxidative preparations are provided herein. In one embodiment, a cosmetic agent for changing the color of keratinic fibers is provided. The cosmetic agent includes a preparation (M1) containing a color-changing component and an oxidizing agent preparation (M2) containing in an aqueous, cosmetic carrier at least hydrogen peroxide as a chemical oxidizing agent and an anionic, polymeric thickener selected from crosslinked or uncrosslinked polyacrylic acid polymers. The cosmetic agent has a viscosity of about 5 to about 100 Pa s. The cosmetic agent is prepared directly before use by blending preparation (M1) with oxidizing agent preparation (M2).