Taking iodine 131 does not necessarily mean that the condition is more serious, taking iodine 131 belongs to a therapeutic means, in the clinic is commonly used in the treatment of hyperthyroidism or thyroid malignant tumors and other diseases, need to be carried out under the guidance of a physician. 1. Hyperthyroidism: patients with hyperthyroidism, such as taking anti-thyroid drugs leading to liver function damage, white blood cell abnormalities or severe allergies and not suitable for surgery, can consider taking iodine 131 for treatment. Most patients will eventually develop hypothyroidism, which can be treated with lifelong levothyroxine sodium supplementation. 2. Thyroid malignant tumor: after thyroid malignant tumor undergoes total thyroidectomy or sub-total thyroidectomy, due to the existence of malignant tumor cells, taking iodine 131 can kill the remaining thyroid malignant tumor cells, so as to achieve the clinical effect of radical cure. Therefore, taking iodine 131 treatment does not indicate that the thyroid disease is more serious, but is a form of treatment, it is recommended that you can consult the endocrinology department of regular hospitals, and consult the doctor in time if you feel unwell.