Preparation before radioactive iodine treatment for hyperthyroidism 1. Avoid iodine-containing drugs and food for 2-4 weeks before taking iodine. 2. Stop taking anti-thyroid drugs, 1 week for those who are taking Tabazol and 2 weeks or more for those who are taking Propecia. 3. Fasting is required before taking iodine. 4. A thyroid scan and 24-hour iodine uptake rate measurement should be done to estimate the dose of iodine to be taken. 5. Avoid strenuous activities for a few days before taking iodine. Precautions after treatment: 1. You should not eat food within 2 hours after taking iodine-131 medication, but you can drink water or a small amount of white thin rice. 2. Pay attention to rest during the treatment period and prohibit strenuous exercise within the last two weeks. 3. You should flush the bathroom more often when you urinate or defecate within one week after taking Iodine-131. 4. Pay attention to relative isolation from children and pregnant women within the last 2-3 weeks. 5. Come back for a follow-up examination about three months after taking iodine-131 treatment to determine whether hyperthyroidism is cured so that treatment measures can be taken. 6. If a series of symptoms of hyperthyroidism such as difficulty in breathing, high fever, deficiency and irritability appear within 2 weeks after taking iodine-131, please go to a nearby hospital for timely treatment and explain to the physician that you have a history of hyperthyroidism. 7. For women of childbearing age, it is best to consider pregnancy only after six months of iodine administration, and for men after three months of treatment.