Hypothyroidism, also known as hypothyroidism, is a generalized low metabolic syndrome due to various causes. Possible causes of hypothyroidism include autoimmune damage, destruction of the thyroid gland, iodine overdose, and antithyroid drugs. 1. Autoimmune damage is the most common cause of hypothyroidism, including Hashimoto’s thyroiditis, atrophic thyroiditis, and postpartum thyroiditis. 2. Thyroid destruction is the second most common cause of hypothyroidism, including thyroid surgery. 3. Excess iodine can cause hypothyroidism in people with underlying thyroid disease. 4. Hypothyroidism caused by antithyroid medications, such as lithium, thioureas, imidazoles, and so on. Patients with hypothyroidism need to seek medical treatment in time to avoid delays.