A new sesqniterpene perogidie componnd, named yingzhaosu A, has been isolatod from the roots of yingzhao (Artabotrys uncinatus (L.) Merr.) (Anonaceae).Yingzhaosu A possesses significant pnysiologioal aotivity.The molecular formula of yingzhaosu A is found to be C₁₅H₁₆O₄ by mass spectrometry.Yingzhaosu A contains two vicinal hydrobyl groups, a six-membered peroxide ring and a double bond.On the basis of degradation reaotions,synthesis of degradation products and spectroscopic data(UV,IR, MS, and NMR.),structure I is assigned to yingzhaosu A.