Abstract:The experiment has shown that the main pathological lesion in hyperthyroidism-type Yin-deficiencY rats resulting from great dose s of T3 is distinct atroptlia of thymus.Other lesions inelude functional changes of adrenocorticat cells and weight decreases of thyroid,adrenal and spleen.Treated with tortoise-shell and tortoise plastion,the structure and weight of these these thymus,thyroid,adrenal and spleell become normal or nearly normal.The fullction of tortnise-shell is basically the same as that of tortoise plastion.