Cosmetic use of a lysate of Bifidobacterium spp.(I) or one of its fractions to treat and/or prevent states of oily scalp, is claimed. An independent claim is included for a cosmetic and/or dermatological composition comprising at least one lysate of at least one microorganism of Bifidobacterium speciesor one of its fractions, in combination with an effective amount of at least one antidandruff active agent, in a medium. ACTIVITY : Dermatological; Antipruritic; Antiinflammatory; Antimicrobial. MECHANISM OF ACTION : None given.