The invention relates to a method for thickening a cosmetic composition by means of an alkali-swellable direct (oil-in-water) emulsion of an acrylic acid-rich ASE or HASE polymer containing a certain amount of AMPS. The use of such emulsions dispenses with the need for surfactants and organic solvents other than water and makes it possible to initiate the thickening effect at a pH of less than 7, the last feature being particularly advantageous for formulations that are to come in contact with the skin.
