Eugenol is the trade name, its generic name is levothyroxine sodium, mainly used for the treatment of multiple causes of hypothyroidism, with the efficacy of replacing thyroid hormone, common side effects include arrhythmia, palpitations, tremor, euphoria, headache and so on. The efficacy of levothyroxine sodium is mainly used as thyroid hormone replacement therapy. Indications include long-term replacement therapy for hypothyroidism caused by a variety of diseases such as congenital hypothyroidism, chronic lymphoid thyroiditis, etc. It is also used in suppression tests for the diagnosis of hyperthyroidism. Contraindications to the drug include hypersensitivity to the drug, tachyarrhythmias, non-hypothyroid heart failure, and patients with recent myocardial infarction. Adverse reactions include angina pectoris, arrhythmia, palpitations, tremor, euphoria, headache, restlessness, insomnia, diarrhea, vomiting, excessive sweating, flushing, weight loss, and spasm of skeletal muscles. The drug should be used under medical supervision.