Most of the patients start to show effect only 2~3 weeks after taking 131 iodine, and the symptoms of hyperthyroidism such as panic, fear of heat and sweating, thick neck and other symptoms will gradually decrease, and the symptoms of hyperthyroidism basically disappear 3~6 months after taking the drug. Therefore, during this period, patients should not be too anxious and should rest well and keep their emotions stable and their spirits happy. Three months after taking 131 iodine, the patient should return to the hospital for a review to evaluate the effect of treatment or to decide whether to take further treatment. Thereafter, return to the hospital for follow-up once in six months and once a year after taking the drug in order to detect problems at an early stage and provide timely treatment. According to the statistics of our hospital, the one-time cure rate of 131 iodine treatment for hyperthyroidism is 96%, so 4% of the patients may need a second treatment. Iodine treatment for hyperthyroidism has few side effects, but hypothyroidism inevitably occurs in a small number of patients. The mechanism of hypothyroidism is complex and not fully understood, but in many cases is related to individual sensitivity differences. Moreover, there is a certain incidence of spontaneous hypothyroidism in patients with hyperthyroidism, therefore, hypothyroidism after 131 iodine treatment for hyperthyroidism is by no means the result of medical malpractice. Hypothyroidism usually occurs 2-3 months after taking the medication, and in a few patients it occurs after 6 months. The main symptoms of hypothyroidism include swollen face, yellow face, fear of cold, poor appetite, abdominal distension, excessive weight gain, generalized muscle pain and swelling, hand and foot cramps and numbness, poor mental health, and drowsiness. Once the above symptoms appear, there is a possibility of hypothyroidism, and the patient should return to the hospital for review in time. It must be pointed out that as long as the patient can return to the hospital for timely review, it is entirely possible to diagnose hypothyroidism at an early stage before the above-mentioned symptoms appear, and to correct them quickly through thyroid hormone replacement therapy, so that the patient can become a completely healthy person and resume normal study, work and life. Therefore, patients with hyperthyroidism treated with 131 iodine do not need to be afraid of hypothyroidism, the key is timely review and early diagnosis and treatment; patients with hypothyroidism should not be pessimistic and disappointed, as long as thyroid hormone replacement therapy is carried out reasonably under the guidance of doctors, they can achieve good results.