Levothyroxine should be taken as a one-time dose with water half an hour before breakfast. L-Thyroxine is a synthetic thyroid hormone that 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 the most commonly used synthetic levothyroxine. For post-surgical papillary thyroid cancer patients, TSH suppression therapy is a very important treatment tool, but clinically, we found that some patients have taken a lot of Eugenol, but their TSH levels are still not well suppressed. Why do some people who take Eugenol and have their thyroid function rechecked do not achieve the expected results? There are many reasons that can affect the absorption of Eugenol, resulting in a decrease in its drug concentration, therefore, oral Eugenol needs to pay attention to the following points: 1, Eugenol drug quality to ensure the purchase of drugs need to be formal channels, the best in the hospital to buy. 2, at the right time to take eugenol Eugenol should be at least half an hour before breakfast (longer is better) will be a day’s dose of one-time with water delivery. 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, soy, strong coffee, milk and soy milk immediately after taking the medication, and do not take calcium tablets, proton pump inhibitors, etc., because they will affect the absorption of Eugenol. 3.Pay attention to the preservation of Eugenol under special temperature condition Eugenol is stored below 25℃, and can be put into refrigerator on hot days in summer. The dosage of Eugenol is often less than one piece, so it should be broken now, 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 the 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, liver 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, when patients take these drugs at the same time, they need to follow the doctor’s advice to increase the dosage of Eugenol. 5. The following factors are rare such as thyroid hormone resistance syndrome, abnormal deiodinase; an even rarer cause is poor pituitary response to T3 alone. Therefore, we should first rule out the 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 thiosulfate, etc. (4) Take the following food medications 2 hours after taking Eugenol orally: (so it is recommended to take Eugenol 2 hours after eating better) animal offal, sesame paste, spinach, shrimp, fungus, red dates, cherries, grapes, peaches, etc. Because Eugenol is only taken once a day, so some people’s dietary habits are properly adjusted, it can be done without affecting the absorption of drugs. Remember to test the effect of taking the medication on time according to the doctor’s instructions.