An object of the present invention is to increasethe rate at which lignan-class compounds (such assesamin and/or episesamin) are absorbed into the body,namely, to provide fast-acting lignan-class compounds.Provided is an oil-in-water emulsion which comprisesa water phase and an oil phase comprising at least onekind of lignan-class compounds dissolved therein andbeing emulsified in the water phase, wherein the oildroplets which serve as a dispersion phase in the emulsionare made finer by high-speed agitation or other method sothat their average particle size is 1000 nm or smaller,preferably 500 nm or smaller, and more preferably 300 nmor smaller, whereby the rate at which lignan-classcompounds are absorbed into the body is improved toimpart immediate action.
