Insufficient secretion of thyroid hormone will lead to a decrease in a person’s entire degree of vitality, mainly manifested as fear of cold, weakness, drowsiness, unresponsiveness, anemia, dry stools, swelling of the face and both lower limbs, bradycardia, and in severe cases, pericardial effusion, pleural effusion, or symptoms such as chest tightness and breath-holding. All of these are caused by a decrease in the production of thyroid hormone levels, which is called hypothyroidism. A test will reveal a significant decrease in thyroid hormone levels and a significant increase in thyroid stimulating hormone levels. For patients with hypothyroidism, if the diagnosis is clear, the treatment is relatively simple, that is, oral replacement therapy with eugenol, and the dose of eugenol should be adjusted by reviewing the thyroid function every 4 weeks. Patients need to take oral replacement therapy with Eugenol for life and cannot stop taking it.