The present invention belongs to the field of nutraceuticals or functional agents with immunostimulating capacity for triggering mechanisms of the innate immune response at a mucosal level. More specifically, it refers to the use of the compound D-fagomine as immunostimulating agent of the innate immune response in the mucosa and for the prevention or prophylaxis of inflammatory processes or diseases associated with an overactivation of the humoral immune response. The invention also relates to a composition comprising D-fagomine for the above referenced application.