Some hypothyroid patients need to take eugenol for life, but if the dose is appropriate, it usually does not affect the patient’s life expectancy. Eugenol is an exogenous thyroxine. Patients with hypothyroidism are unable to secrete and release sufficient amount of thyroxine due to thyroidectomy or thyroid lesions, and the lack of thyroxine in the body can lead to some pathological conditions, so they need to supplement with exogenous thyroxine to replace the function of the thyroid gland. In general, as long as the dosage is controlled within a reasonable range, there are no side effects and the life expectancy of the patient is not affected. However, if the medication is suddenly stopped during the course of administration, it may lead to severe stress reactions in the organism and endanger the life of the patient. In addition, hypothyroid patients should undergo thyroxine replacement therapy as early as possible. Those who can recover their thyroid function can gradually reduce the dosage, while those who cannot recover must take it for life and cannot stop taking it without authorization.