Abstract: To prepare an aqueous dispersion of lamellar lipid vesicles, at least one lipid is dissolved in at least one water-immiscible organic solvent; the organic phase thus obtained is added to an aqueous phase in such amounts that a dispersion of the oil-in-water type is obtained by vigorous stirring; the evaporation of the solvent(s) is carried out with vigorous stirring, the continuous phase of the dispersion always remaining the aqueous phase; and, should it become necessary, the dispersion is concentrated. The process can be carried out at low temperature (of the order of 35.degree. to 55.degree. C.), which makes it possible to encapsulate in the aqueous phase or to introduce into the vesicle sheets heat-sensitive active substances; the lipid concentration in the organic phase can reach up to 50% by weight.