Abstract:The therapeutic effect of Tibetan medicine on the experimental secondary Echinococcus granulosus cysts(CE) was investigated, in which the ultrastructural observation on CE was carried out in mice undergone Tibetan medicine therapy 90 days after treatment, and the major judging indices included wet weight of CE, inhibition rate and histopathological changes in CE as demonstrated by light and electron microscopy. It was found that obvious damage on the cyst wall of hydatid could be observed under light microscopy on the 90 th day of treatment. Under electron microscopy, the laminated layer of cysts appeared to be not so homogenous, and the microvilli on the germinal layer became shorter and appeared to be unclear. In addition, pyknosis and karyorrhexis could be demonstrated in cells. It is evident that the Tibetan medicine shows certain therapeutic effect on E.granulosus cysts