Abstract: The ultrastructural changes of the germinal membrane of human Echinococcus granu-losus cyst and protoscolices treated with total alkaloids isolated from Corydalis stricta Steph for 30 days(15mg/kg·d, po) were observed. Cysts from the total alkaloid-treated patients were shown by transmission electron microscope to have disturbance in the arrangement of organelles dilatation and disruption, of microtubules, increase in size and number of lysosomes, decrease in number of Golgi bodies, and degeneration of mitochondria. Under scanning electron microscope many pits were observed arising from the outer and inner surfaces of the germinal membrane together with disruption of the external plasma membrane, hook detachment, sucker deformity of evaginated protoscolices. It seems clear that the total alkaloid has a profound intracellular effect on Echinococcus granulosus cysts and protoscolices in humans and might be a promising drug for human hydatid disease.