Non-coloring cosmetic composition comprises, in an aqueous medium, at least 20 wt.% of one or more quaternary ammonium cation type ionic liquids, and one or more non-silicone fatty substances, where the weight ratio of ionic liquids and fatty substances are >；= 5. An independent claim is included for a method of cosmetic treatment of keratin materials, preferably human keratin fibers such as hair, comprising applying the composition to the keratin materials, and then optionally rinsing after a possible exposure time.
