The present invention relates to bleaching composition for keratin fibres, especially human hair, comprising at least one compound with bleaching and/or highlighting effect and a specific chelating agent. The object of the present invention is a substantially water free bleaching and/or highlighting composition for keratin fibres, especially human hair, comprising at least one compound with bleaching and/or highlighting effect and a polyhydroxy carboxylic acid and/or its salt as a chelating agent. Suitable and most preferred is gluconic acid and its salts especially mono valent cation salts such as sodium, potassium and ammonium salts.
