Currently, the prevalence of thyroid disorders is increasing and more and more patients are taking Eugenol orally. The active ingredient of Eugenol is levothyroxine (L-T4), which has a clear content and good efficacy and is mainly used as a supplement and replacement therapy for hypothyroidism caused by various reasons. L-T4 is a synthetic thyroxine, which can be easily absorbed and utilized to produce effects similar to those of human thyroid hormones, and can replace lost or missing thyroid hormones. Euthyroxine is one of the most commonly used synthetic levothyroid hormones. For example, for patients with papillary thyroid cancer, TSH suppression therapy is a very important treatment tool, but clinically, we find that some patients have taken a lot of Eugenol, but their TSH levels are still not well suppressed. Why do some people have poor results with oral eugenol? In fact, many reasons can affect the absorption of Eugenol, resulting in a decrease in its drug concentration, therefore, oral Eugenol needs to pay attention to the following issues: 1, the source of Eugenol It is recommended to buy Eugenol from the regular hospital. 2, Eugenol oral time Eugenol should be taken in a one-time dose with water half an hour before breakfast. Half an hour before breakfast may be difficult to grasp and easy to forget, it is recommended to take it with plain water immediately after waking up in the morning and do not eat any food within half an hour. Do not drink grapefruit, soybeans, strong coffee, milk and soy milk immediately after taking the medicine, and do not take calcium tablets, proton pump inhibitors, etc., because they will affect the absorption of Eugenol. 3, the preservation of Eugenol Eugenol is stored at 25 ℃ or below, and can be refrigerated on hot days in summer. The dosage of Eugenol is often less than one piece, so it should be eaten now and broken, and the remaining broken Eugenol is recommended to be stored in a sealed vial to avoid affecting the efficacy of the drug due to moisture. 4.Factors affecting the absorption and metabolism of Eugenol Eugenol is absorbed in the small intestine (mainly in the duodenum and jejunum) after oral administration, but stomach acid affects its absorption, usually the higher the stomach acid, the less it is absorbed. In healthy individuals, the blood concentration peaks about 2 hours after taking the drug. If the patient has gastrointestinal diseases, celiac disease, cirrhosis, absorption disorder syndrome such as gastric acid deficiency, etc., these conditions can affect the absorption of Eugenol. In addition, because Eugenol contains lactose, some people have lactose intolerance, such as milk intolerance, etc. These patients may be intolerant to Eugenol. Eugenol clearance is mainly metabolized in the liver, and any drugs with liver enzyme-inducing effects, such as barbiturates, phenytoin sodium, carbamazepine, rifampin, etc., will accelerate the metabolism of L-T4 and increase liver clearance, resulting in shorter duration of action and lower blood concentration in the body. Therefore, patients taking these drugs at the same time need to follow medical advice to increase the dosage of Eugenol. 5. Rarer factors such as thyroid hormone resistance syndrome, deiodinase abnormalities; an even rarer cause is the pituitary gland simply responding poorly to T3. Therefore, we should first rule out factors affecting the absorption of eugenol, then try to increase the dose of eugenol or replace part of L-T4 with thyroid tablets to take, because thyroid tablets contain T3 components, and then review the thyroid function. If TSH is suppressed, it suggests that deiodinase abnormalities may be the cause in this group of patients. However, it is worth mentioning that deiodinase abnormalities will only occur in patients after total thyroidectomy, so it is not common. (1) Take the following drugs 4 hours after taking Eugenol orally: aluminum hydroxide, calcium carbonate, cholestyramine, aluminum thioglycollate, bile acid chelator (cholestyramine, colestipol), vitamin D and calcium, etc. (2) Drink the following beverages 4 hours after taking Eugenol by mouth: grapefruit, soy, strong coffee, milk, yogurt, soy milk and high fiber diet. (3) Take the following medications 2 hours after taking Eugenol: calcium carbonate, ferrous sulfate, aluminum hydroxide, aluminum thioglycollate, etc. (4) Take the following foods 2 hours after taking Eugenol orally: animal offal, sesame paste, spinach, shrimp, fungus, red dates, cherries, grapes, peaches, etc.