Objectives: The present study was carried out to investigate the effects of YJT on experimental hypothyroidism induced by sodium perchlorate and methimazolein in mice. Methods: 30 one-month-old C57BL6 mice were decided into 4 groups: 1) normal (n=6), 2) sodium perchlorate and methimazolein-induced hypothyroidism control (n=8), 3) hypothyroidism mice treated with low YJT (n=8), 4) hypothyroidism mice treated with high YJT (n=8). Sodium perchlorate and methimazolein were administered for 4 weeks, YJT (low and high) was administered for 2 weeks after sodium perchlorate and methimazolein were initiated for a total duration of 2 week. The changes were observed : weight of body, T3, T4, TSH, follicular cells in the thyroid tissues, LDL cholesterol, HDL cholesterol, triglyceride and free fatty acid, FBG, AST, ALT and so on. Results: YJT did not affect body weight gain. YJT restored free T4 level decreased by sodium perchlorate and methimazolein and prevented shrinking of follicles and proliferation of follicular cells in the thyroid tissues. In addition, YJT lowered total and LDL cholesterol levels elevated by sodium perchlorate and methimazolein respectively and ameliorated distribution of fat in liver tissues. In addition, the effect on fasting blood glucose (FBG), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also investigated. Conclusions: These data suggest that YJT can be used to treat woman patients which are accompanied with hypothyroidism relatively safely.