Hypothyroidism or post-thyroid surgery due to thyroid gland removal, thyroid function will be affected, the need to apply thyroxine replacement therapy, there are many patients and friends worried about the long-term oral thyroxine what effects, in fact, thyroid tablets if the dosage is appropriate without any adverse reactions. Overdose can cause tachycardia, palpitations, angina, arrhythmia, headache, nervousness, excitement, restlessness, insomnia, skeletal muscle spasm, muscle weakness, tremor, sweating, flushing, fear of heat, diarrhea, vomiting, weight loss and other symptoms similar to hyperthyroidism. All symptoms may disappear with dose reduction or discontinuation of the drug. Non-overdose application is not contraindicated in pregnant women. In addition, since thyroxine accelerates the loss of calcium, it is recommended to take oral eugenol with appropriate calcium supplementation, preferably with a combination of calcium and vitamin D. It is especially important for postmenopausal women to pay attention to calcium supplementation. Calcium supplementation should be around 1000 mg per day after differentiated thyroid cancer surgery.