It is an objective of the present invention to provide a composition that is sufficiently safe to allow daily ingestion and that has an ability to promote the secretion of s-IgA into saliva in a continuous and age-independent manner. The above objective is achieved by the composition for promoting secretion of secretory IgA, comprising as an active ingredient Okinawa mozuku-derived fucoidan with a recommended daily intake of 1,000 mg or more. The composition has the mucosal immunostimulatory effect, anti-infection effect or anti-allergy effect and is expected to be used for ameliorating, mitigating, suppressing, treating or preventing diseases or symptoms on which these effects are expected to work, such as bacterial infection, viral infection, protozoan infection, food allergy, pollenosis, gastritis, enteritis, diarrhea, ulcerative colitis, rhinitis, bronchitis, bronchial asthma, Löffler's syndrome and stomatitis, as well as any symptoms resulting therefrom. The composition is also expected to be used in immunotherapies and induction of immunotolerance.
