You can eat iodized salt 1 month after iodine-131 treatment. Iodine-131 is an internal radiation therapy of the isotope iodine-131, which is absorbed by the thyroid gland through oral iodine-131, after which gamma rays and beta rays are released in the body, which in turn kill the diseased cells of the thyroid gland. It can be used for hyperthyroidism that has failed to respond to conservative drug treatment and for certain patients who need further treatment after surgery for differentiated thyroid cancer, such as papillary thyroid cancer with relatively large tumors or lymph node metastases or distant metastases. Iodine-131 treatment causes radioactive damage to the thyroid cells. At this time, the release of thyroid hormones increases, leading to further aggravation of thyroid disease symptoms. Therefore, patients should not eat iodized salt for 1 month after iodine-131 treatment, and can replace it with non-iodized salt. At the same time, they should try to have a low iodine diet and not eat foods with high iodine content, such as seaweed and nori, etc. They should review their diet after 1 month of recovery and change it appropriately under the guidance of doctors.