Abstract: Provided are a pharmaceutical product capable of treating vitiligo by thickening the epidermis at a vitiligo-affected site, which has been thinned, to thereby accelerate pigmentation, and a method of accelerating pigmentation by thickening the epidermis. Vitiligo can be treated by using a compound having an epidermis thickening action, for example, a therapeutic agent for a skin ulcer which is used in the treatment of burn ulcer, crural ulcer, diabetic ulcer or post-operative ulcer, or a therapeutic agent for bedsore.