It is a synthetic levothyroxine that works in the same way as the body’s natural thyroid gland, and the body is unable to distinguish between endogenous and exogenous levothyroxine. Side effects of levothyroxine are rare, but if the dose exceeds the individual’s tolerance or is overdosed, especially if the dose is increased too rapidly at the beginning of treatment, some of the following symptoms of hyperthyroidism may occur, including arrhythmia, tachycardia, palpitations, angina, headache, muscle weakness and cramps, flushing, fever, vomiting, menstrual disorders, pseudotumor, tremor, restlessness, insomnia, excessive sweating , weight loss, and diarrhea. In these cases, the patient’s daily dose should be reduced or discontinued for a few days. Once the above symptoms disappear, the patient should carefully restart the medication, so it can be said that Eugenol has no side effects that cause abnormal liver function indicators, so there is nothing to worry about.