Objectives: The symptoms of hypothyroidism are fatigue, cold intolerance, arthralgia, muscle cramps, dry skin and etc. Although hypothyroidism is a relatively common endocrinical disease, we do have many difficulties treating it effectively. The symptoms of hypothyroidism are similar to those of Yang-deficiency in Oriental medicine. Epimedii Herba is a popular herb that has the effect of tonifying the kidney and strengthening Yang in Oriental medicine. In this study, we investigated the therapeutic effects of Epimedii Herba on a hypothyroidism rat model induced by PTU(6-Propyl, 2-thiouracil). Methods: 24 two-month-old Spargue-Dawley(SD) rats were divided into 4 groups: 1) normal(n=6), 2) PTU-induced hypothyroidism control(n=6), 3) hypothyroidism rat treated with Epimedii Herba(n=6), 4) hypothyroidism rat treated with levothyroxine(n=6). PTU was administered for 4 weeks, Epimedii Herba and levothyroxine was administered for 2 weeks after PTU was initiated for a total duration of 2 week. At the end of the experiment, blood samples from all the rats were taken from their hearts and were analyzed. Results: In comparison with normal group, the PTU-induced control group significantly showed hypothyroidism with low T3, T4 and high TSH. In Epimedii Herba group, T4 was significantly increased(p<0.05). There was no significant difference in TSH between the Epimedii Herba treatment group and the control group. And no significant differences were observed in biochemical labs and weight between the Epimedii Herba group and the control group. Conclusions: These results suggest that Epimedii Herba could help thyroid cells to produce thyroid hormones. And no significant side effects related with Epimedii Herba were found, suggesting that it is safe to administer. According to these results, Epimedii Herba may be a safe alternative medicine for hypothyroidism.