Abstract: A preparation for bleaching teeth, comprising 0.3 to 30% by weight of a bleaching component selected from hydrogen peroxide or carbamide peroxide, 4 to 80% by weight of water, 0.05 to 1.00% by weight of a complexing agent selected from the group of the biphosphonates, and 0.1 to 3.0% by weight of a thickener, the preparation exhibiting a pH value in the range from 4 to 7 and a viscosity in the range from 1000 to 120 000 mPa·s (measured with a Brookfield RVF; up to 40 000 mPa·s spindle 4/4 rpm; from 40 000 mPa·s spindle TE/4 rpm; Helipath), the preparation being used in particular in an applicator which exhibits an applicator head which can be impregnated with the preparation to act upon the surfaces of the teeth of the user.