High free thyroid hormone is mostly seen in hyperthyroidism, the most common cause is diffuse toxic goiter, and fever, poor rest, stress, heredity and so on have a certain relationship, it is caused by excessive secretion of thyroid hormone. The patient’s main manifestations are panic, increased appetite, wasting, emotional, finger trembling, some will appear thyroid protruding eyes, check the thyroid gland can be enlarged, nodules, the need for timely examination and treatment, the drug needs to be used under the guidance of a doctor, do not blindly use their own medication.