Doxycycline is the generic name of doxycycline, and its contraindications include enzyme-inducing drugs, antacids, calcium, magnesium and iron ion-containing drugs, hepatotoxic drugs, lipid-regulating drugs, and estrogen-containing contraceptives. 1. Enzyme-inducing drugs: coadministration with enzyme-inducing drugs such as barbiturates, carbamazepine and other drugs can reduce doxycycline blood concentration, and it is necessary to adjust the doxycycline dosage or interval time. 2. Antacids: Taken with antacids such as sodium bicarbonate, it is not favorable to drug absorption and is easy to reduce its drug activity. 3. Calcium, iron, magnesium ion-containing drugs: with calcium, iron, magnesium ion-containing drugs, such as calcium lactate, calcium gluconate and other drugs, easy to form insoluble compounds with its metal ions, is not conducive to drug absorption. 4. Hepatotoxic drugs: with hepatotoxic drugs such as anti-tumor chemotherapy drugs, easy to aggravate liver damage. 5. Lipid-regulating drugs: taking with lipid-regulating drugs such as Kaolai Tipo is not conducive to drug absorption; if you need to take the same drug, you should take it at intervals. 6. Estrogen-containing contraceptives: taking with estrogen-containing contraceptives will reduce the effect of contraceptives and increase menstrual bleeding. Doxycycline is a prescription drug and must be prescribed by a doctor in accordance with the condition before use; it should not be used privately according to the instructions to avoid drug risks and delayed medical conditions.