The present invention relates to a method for preparing an extract from one or more kinds of plant materials such as Indigo Naturalis, and the extract itself. The invention also relates to a composition comprising the extract, as well as the use of the composition in medical or cosmetic applications.本発明は、インジゴ・ナチュラリス等の1種又は複数種の植物原料からエキスを調製する方法、及びエキス自体に関する。本発明はまた、エキスを含む組成物、並びに医学又は化粧用途における組成物の使用に関する。