Yecao (scientific name: dipsacus asperata? Lynn. ) is a biennial herb of Dipsacaceae, 2 meters high; The stem is hollow and stout, erect, the basal leaves are petiolate and inlaid, the leaves are long and obovate, the stem is supported at the base of the leaves in a cup shape, the leaves are long and lanceolate, and the main veins on the back of the leaves are prickly. The head is oblong, the total bracts are linear-lanceolate, the bracteoles are oblong, the edges are ciliate, the flowers are purple or white, the calyx is discoid, and the lobes are unequal; Stamens inserted on corolla tube; The ovary is inferior and enclosed in a saccate involucre. Achenes are oval and brown. It blooms in June-July and bears fruit in August-September.