Abstract: The crystalline thevetin was isolated from the kernels of Thevetia peruviana Schum. by Huang Ching-chang (1956). It melts at 190-196℃. The cat unit of Thevetin is 0.9752mg/kg±0.0239 (S.E.). The elimination rate of this glycoside in the liver of cat is 0%. When the pylorus of cat was ligated and 1 cat unit of thevetin was then injected into the duodenum, the rates of the enteral ab- sorption of this drug after 2, 4, and 6 hours are 12.77, 37.79, and 8.14% respectively.