Yuan-Hna (Thymelaea,oeae,Daiphne genkwa Sieb.et Zuce.) has been used in traditional Chinese medicine for various therapeutic purposes.Recently,the alcoholic extract of its flower was found to be effective as abortifioient on clinical trials.A new diterpene orthoester,yuanhuafine,C₂₉H₃₂O₁₀,m/z M+540.1977(calcd.540.1995),[α]_D^15.5+39.1° (o.0.5145,CHCl₃),colorless amorphous powder,has been isolated in 0.011% yield from the flower.Besides,a known diterpene orthoester,12-benzoxy-daphnetogin(2) was obtained in 0.0013% yield from the root of the same plant.The structure of yuanhuafine was found to be 1 according to spectral and chemical evidences.The two compounds cause severe irritation on skin.The abortifaoient dose of 1 in monkey was shown to be 200 μg/animal.