The present invention provides a human .beta.-defensin secretion promoter that can be used in various forms, such as external preparation, internal preparation, food, etc., and promotes human .beta.-defensin secretion. An organic acid has an effect of promoting the secretion of human .beta.-defensin, particularly human .beta.-defensin-2, and therefore the organic acid is used as an active ingredient of a human .beta.-defensin secretion promoter. Furthermore, by adding the human .beta.-defensin secretion promoter to external preparations, internal preparations, or foods, a human .beta.-defensin secretion promotion effect can be imparted thereto.