The causes of hyperthyroidism to hypothyroidism and the measures to deal with it are as follows; 1. Overdose of hyperthyroidism treatment drugs: lead to drug hypothyroidism, patients need to gradually reduce or stop using the drugs for hyperthyroidism, regularly review and retest the thyroid function after a period of time; 2. Excessive hypothyroidism: the symptoms of hypothyroidism can be improved by means of supplemental eugenol, i.e. thyroid hormone; 3. Mild hypothyroidism: after stopping the drugs or reducing the dosage, the patient will recover after a period of time, and then continue the treatment; 4. 4. natural course: i.e. hyperthyroidism in early stage and hypothyroidism in late stage, such as Hashimoto’s thyroiditis, patients do not need special treatment; 5. long-term hypothyroidism: patients need thyroid hormone supplementation for treatment. Therefore, for hyperthyroidism to hypothyroidism, it should be distinguished which cause is responsible. If the cause is pharmacological, intervention can be made or the medication can be adjusted to make it recover. For the process of disease regression, i.e., from hyperthyroidism to hypothyroidism, this is the natural regression of the disease. The medication should be adjusted according to its specific manifestations, or its immune function should be adjusted, or its hypothyroidism symptoms should be monitored to improve.