The present invention relates to a method for isolating flavonoids such as cochlioquinone or chrysoeriol from a rice plant inoculated with a whitebacked planthopper. The method of the present invention, for example, facilitates not only the fast production of flavonoids such as cochlioquinone or chrysoeriol but also the mass-production of flavonoids such as cochlioquinone or chrysoeriol with high efficiency in addition to the advantage of saving costs. Therefore the method of the present invention can be effectively used for the production of flavonoids such as cochlioquinone or chrysoeriol and also be used in various fields using the same.
