Most of conventionally known IgA antibody secretion promoters relate to IgA antibody production in the intestine, and there are known few IgA antibody secretion promoters relating to an IgA secretion promoting action and an infection suppressing action in organs of the respiratory system such as the oral cavity, the nasal cavity, and the respiratory tract. Thus, provided is a pharmaceutical composition having an IgA secretion promoting action in organs of the respiratory system such as the oral cavity and the respiratory tract as well as in the intestine. An IgA secretion promoter containing a corn poppy extract has an IgA secretion promoting action in the oral cavity and the respiratory tract as well as an IgA secretion promoting effect in the intestine. Therefore, ingestion of the extract can suppress infection with viruses and bacteria and prevent onset of allergy.
