Avoid iodine-containing foods and keep your heart rate below 160 beats for 2-4 weeks prior to taking iodine 131 treatment. Stop taking anti-thyroid drugs. Check blood and urine routines and observe the health condition of the body. Patients should rest in bed for a few days before and after taking iodine 131. The effect appears 3-4 weeks after taking the medication, some patients can improve their symptoms only 6 months after taking the medication, and some need multiple courses of treatment. There is a possibility of recurrence after treatment and regular review is needed. For 1 month after treatment, eat a low iodine diet and avoid squeezing the thyroid gland.