Elevated free thyroid hormone needs to be clarified as to the cause of the disease, which may be due to laboratory errors or diseases such as subacute thyroiditis or Graves’ disease, which can be cured. In the early stages of subacute thyroiditis, thyrotoxicosis may occur, accompanied by elevated free thyroid hormone, decreased TSH, as well as symptoms such as thyroid gland pressure, fever, etc. Most patients with subacute thyroiditis can be cured. In Graves’ disease, elevated free thyroid hormone, accompanied by decreased TSH and positive TRAB antibodies, can be treated with antithyroid drugs such as methimazole as prescribed by the doctor, or surgery or iodine 131 radiation therapy if the condition is serious. It is recommended to go to the hospital and ask the doctor to make a judgment if the free thyroid hormone is elevated.