Eugenol, also known as levothyroxine sodium, is a thyroxine supplement that is used clinically for thyroxine replacement therapy for thyroidectomy, hypothyroidism, and overdose of antithyroxine medications. Because food can interfere with the absorption of Euthyrox, Euthyrox should be taken as a one-time one-day dose with water on an empty stomach half an hour before breakfast. Because thyroxine is a hormone that we have in our body itself, we need to prevent it from overdosing during use. The drug should be used to regularly monitor the thyroid function, thyroid function measurements in the T3 level of the elevated level is an effective indicator of drug overdose, we can adjust the dose of Euthyrox according to the results of the thyroid function. Because levothyroxine, a component of Euthyrox, is a hormone found in our bodies, the side effects of this drug are minimal. Side effects are mainly manifested by symptoms similar to hyperthyroidism caused by overdose, so we can reduce its adverse effects by adjusting the dosage, for some patients with hypothyroidism need to take it for life.