Cosmetic hair treatment agent free from hydrogen peroxide and/or the addition products thereof to organic and inorganic compounds and having, in a cosmetic carrier, at least one surface-active agent chosen from anionic, amphoteric and/or zwitterionic surfactants, and at least one acetylpyridinium derivative of formula (I) for improving the general condition of the fibers, for reducing hair damage in the interior of the hair and for increasing the elasticity of the hair.