Disclosed is a method for producing a composition for oral ingestion having an immunostimulating action, the method comprising: orally administrating a Bifidobacterium to a rat comparing mRNA profiles in milk of the rat observed before and after the administration determining mRNAs of which amount in milk of the rat observed after the administration increases by 1.5 times or more of amount in milk of the rat observed before the administration as mRNA functioning in an immunostimulating manner and adding a single kind of mRNA or arbitrary two or more kinds of mRNAs selected from the group consisting of the determined mRNAs to a base for a composition for oral ingestion. Also disclosed is a method for producing a composition for oral ingestion having an immunosuppressive action, the method comprising: orally administrating a Bifidobacterium to a rat comparing mRNA profiles in milk of the rat observed before and after the administration determining mRNAs of which amount in milk of the rat observed after the administration decreases by 0.67 times or less of amount in milk of the rat observed before the administration as mRNA functioning in an immunosuppressive manner and adding a single kind of mRNA or arbitrary two or more kinds of mRNAs selected from the group consisting of the determined mRNAs to a base for a composition for oral ingestion.
