The invention relates to a foam formulation comprising an emulsion, comprising an oil phase and an aqueous phase, wherein the emulsion comprises at least one triterpenoid. Further the invention relates to anemulsion comprising an oil phase and an aqueous phase, wherein the emulsion comprises at least one triterpenoid selected from the group consisting of betulin, betulinic acid, lupeol, erythrodiol, oleanolic acid, (C1-C6) alkyl esters of the aforementioned acids, or mixtures thereof, and wherein the oil phase comprises at least one membrane-forming substance forming a lamellar arranged membrane in the emulsion.
