Objectives : The aim was to study experimentally the effects of Danggwisaeyeoktang(當歸四逆湯) on the hypothyroidism of rats induced by thiouracil. Methods : Spargue-Dawley rat were separated into three groups. Except normal group, the other two groups were treated with thiouracil 50mg/kg/days for 30 days by oral administration. Among the two group, one group was treated DGSYT extract 0.54g/kg/days for 20 days separately. T3-uptake;, T3, T4, TSH, hematological values, enzyme activity, total cholesterol and Na+ content charge in the Serum of rats were measured after medication of solid extract of DGSYT. Result : As a result of this study, in the serum T3-Uptake and T4 level, hematological values and sodium were increased in DGSYT group compared to controls. The serum TSH, total cholesterol and body weight were decreased in DGSYT group compared to controls. Conclusion : According to the above results, it is suggested that DGSYT is effective to cure hypothyroidism.