Objective To observe the effect of hyperthyroidism decoction on thyroid hormone and thyroid pathological changes of ex-perimental hyperthyroid rats. Methods 40 rats were randomly divided into four groups: Normal group,hyperthyreosis model group, western drugs control group and hyperthyroidism decoction group. The model rats were constructed by drenching Youjiale. Hyperthyroidism decoction group were given hyperthyroidism decoction of respective dosage, western drugs control group were given propylthiouracil. The serum contents of T3, T4, FT3, FT4 and TSH were determined by radio-immunity metho...