Thyroid hormone acts on almost all cells of the human body and has the function of promoting metabolism, increasing excitability of the nervous system, as well as promoting growth and development, causing respiration and heart rhythm to speed up and increasing heat production of the body. Its high level is affected by both diet and disease: 1. Excessive iodine intake: If you consume excessive iodized salt for a long time in daily life, or consume too much food with high iodine content, such as kelp and seaweed for a long time, it will easily lead to excessive iodine in the body, which will stimulate the thyroid gland to secrete too much thyroid hormone and cause an increase in thyroid hormone in the body; 2. Thyroiditis: The thyroid gland is invaded by inflammation, which reduces its function and causes excessive thyroid hormone. This causes excessive thyroid hormones to be released into the blood, resulting in high hormone levels. Drugs used to treat thyroiditis include methimazole, propylthiouracil, levothyroxine, etc.; 3. Subclinical hypothyroidism: referred to as subclinical hypothyroidism, usually caused by damage to the thyroid gland. The main treatment is to take levothyroxine sodium under the guidance of a doctor. 4. Autoimmune diseases: such as Graves’ disease, some patients have autoantibodies in the serum that can react with the thyroid gland, which can stimulate the thyroid gland and cause high thyroid hormones, leading to hyperthyroidism. 5. Hypothalamic-pituitary lesions: hypothalamic-pituitary lesions can lead to hormonal changes in the body abnormalities and symptoms of elevated thyrotropic hormone and elevated adrenocorticotropic hormone, common diseases such as pituitary tumors.