Esters of oligo-hydroxycarboxylic acids have the general formula ( ): wherein at least one of the radicals R1, R4 or R5 is a linear or branched aliphatic hydrocarbon radical having 6 to 30 carbon atoms and 0, 1, 2 or 3 double bonds. Cosmetic and pharmaceutical agents contain said esters. These esters are effective as thickeners, in particular for compositions containing surfactants.
