To provide medicines, health foods, or a cosmetics for simply treating atopic dermatitis with a method having few side-effects.

This is an internal medicine containing mucine and/or mucin, a skin medicine for external use, a supplement, a vinegar for drink, foundation, a mascara, an eye shadow, a lip stick, a gross, a blush, a manicure, a pencil, a lotion, an emulsion, a face-wash, a creme, a facial mask, a hair tonic, a perfume, a tooth paste, a shampoo, a rinse, treatment, a soap, or a bath agent. Mucine can be prepared by extraction with water or an alcohol of, for example, Japanese onion, onion, chive, shallot, garlic, Japanese yem, iseimo, or Chinese yem. Mucin can be obtained by extraction with water or an alcohol of Jew's marrow, Japanese yem, aroid, tsukuneimo, nameko, ashitaba, lotus root, Basellaceae, or fermented soybeans.