There are several commonly encountered problems that hyperthyroid patients need to be aware of before and after iodine-131 treatment: 1. Iodine-131 needs to be stopped before treatment with iodine-containing drugs and food. If anti-thyroid medication is being administered, it is usually necessary to discontinue: methimazole for more than 3 days; propylthiouracil for more than 2 weeks. In special cases, discontinuation of medication should be arranged according to the doctor’s decision. 2. Female patients of childbearing age should pay attention to exclude the possibility of pregnancy. 3. Iodine-131 should be taken after two hours of fasting on the day of treatment, and it is better to wait for 2 hours after taking the drug before eating (so that the drug can be absorbed more fully). During this period of time, you can drink moderate amount of water. Be careful not to spill the liquid when taking liquid Iodine-131 orally. In case of nausea and vomiting, ask medical personnel to handle it in time. 4. Within one week after iodine-131 treatment, pay attention to rest and recuperation and drink more water appropriately. Avoid sharing utensils with others. 5. For those who have good family living conditions, it is advisable to use an independent bathroom for one week. Those who share the bathroom should pay attention to avoid urine splashing, prevent sanitary ware and ground contamination, and flush clean after defecation. 6, 1 week after treatment should avoid unnecessary close and prolonged contact with others (close means within 1 meter, long means more than 3 hours). For children under three years old and pregnant women, it is advisable to avoid close and prolonged contact for a longer period of time. 7. Within one month after treatment, avoid consuming foods high in iodine (such as kelp, nori, etc.) and avoid using iodine-containing drugs (such as X-CT contrast agents). 8. Patients with thyroid proptosis should strictly abstain from smoking and alcohol. 9, pay attention to proper rest, avoid strain and mental stimulation, and pay attention to the prevention of infection. 10.There will be swelling or discomfort in the neck for 1-2 weeks after treatment, so be careful not to touch or even press the neck to avoid aggravating the condition. 11.If there is heavy sweating or fever, body temperature >38℃; nausea, vomiting, diarrhea, irritability; heart rate >140 beats/min. It may indicate the possibility of hyperthyroidism critical phase, if any of the above conditions should immediately seek medical attention. 12. Men and women of childbearing age should pay attention to contraceptive measures. Female patients with hyperthyroidism should not become pregnant until at least six months after receiving iodine-131; male patients with hyperthyroidism should use contraception for at least four months after receiving iodine-131. Please consult your treating doctor for special cases. If the doctor has other complementary treatments, the patient should follow them as well.