The main contraindications to taking targeted drugs are unauthorized dose adjustment, eating food that inhibits CYP3A4 enzyme activity, and eating drugs that induce CYP3A4 enzyme production. 1. Unauthorized adjustment of the dose: patients need to take targeted drugs under the guidance of the doctor, to strictly comply with the time and dose of medication, on time and according to the amount of drugs, which is conducive to the maintenance of blood concentrations in the blood, the patient should avoid unauthorized increase or decrease in the dose of medication. 2. Eating food that inhibits CYP3A4 enzyme activity: Since targeted drugs are metabolized by CYP3A4 enzyme, patients should avoid eating food that inhibits the activity of CYP3A4 enzyme such as poppy, pomegranate and grapefruit. 3. Drugs inducing CYP3A4 enzyme production: patients should avoid drugs inducing CYP3A4 enzyme production such as carbamazepine and rifampicin during the period of taking targeted drugs, so as to avoid high content of CYP3A4 enzyme in the body and shorten the time of drugs staying in the body. It is recommended that patients should follow the doctor’s instructions to treat with targeted drugs, and should not use drugs without authorization. Patients should go to the hospital regularly to monitor the liver function or kidney function during the medication period to prevent the targeted drugs from causing damage to the liver and kidneys.