Hyperthyroidism is usually due to excess iodine, not excess iodine, but it has to be analyzed on a case-by-case basis and depends on the cause of the hyperthyroidism. A common cause of hyperthyroidism is Graves’ disease, or toxic nodular goiter, which is due to excess iodine. Toxic thyroid adenoma can also cause hyperthyroidism, which is also a common cause. It is not related to too much iodine or too little iodine, but is caused by the tumor itself, which produces too much thyroid hormone, thus causing hyperthyroidism. In addition, the rare causes of hyperthyroidism, such as pituitary TSH adenoma, are mainly due to the secretion of large amounts of TSH by the pituitary gland, which will promote the secretion of thyroid hormones by the thyroid gland, thus causing hyperthyroidism. The rare cause of hyperthyroidism is iodine hyperthyroidism. Long-term use of iodine-containing foods and iodine-containing drugs can cause hyperthyroidism, which is caused by too much iodine.