Potassium iodide is mainly used clinically for the prevention and treatment of endemic goiter, as well as before preparing for surgery for hyperthyroidism or when rescuing hyperthyroidism crisis. Endemic goiter is mainly caused by iodine deficiency, and potassium iodide can be used as an iodine supplement for effective prevention and treatment. However, with the current popularization and promotion of iodized salt throughout the country, endemic goiter has become relatively rare. Potassium iodide or other iodine-containing preparations are given prior to preparing for surgery for hyperthyroidism in order to reduce the risk of surgical bleeding. The drug is selected for rescue therapy in some cases of hyperthyroidism crisis. It should be noted that patients with iodine allergy, as well as infants and young children usually can not use it. It is recommended to take the drug under medical supervision.