Thyroxine tablets are needed to supplement the insufficient thyroxine secretion after thyroid surgery, and are mainly indicated for patients with chronic lymphatic thyroiditis, nodular goiter and postoperative thyroid cancer. Clinically, surgical resection is the main means of treating nodular goiter. According to foreign studies, the recurrence rate of such surgical patients in the postoperative period has been reported domestically to be 10% to 30%. Whether metastasis or recurrence of thyroid cancer after surgery has a significant relationship with the scope of surgical resection, in addition to the correctness or otherwise of the choice of the first treatment program. According to statistics, the recurrence rate after simple tumor resection is 40%-60%, and the recurrence rate after thyroid lobectomy of the tumor and its affected side is 10%-20%. In addition, the degree of malignancy of thyroid cancer also determines the recurrence rate, that is to say, the higher the degree of malignancy, the higher the possibility of postoperative recurrence or distant metastasis. An effective and simple measure that is important to prevent recurrence of these diseases after surgery is to take enough thyroxine. The suppression of TSH secretion, which brings TSH close to or equal to zero, deprives thyroid nodules or thyroid tissues that may form nodules of the impetus to grow, thus preventing the recurrence of nodular goiter and thyroid cancer.