Before tooth extraction, the patient should receive systematic preoperative examination and evaluation, exclude contraindications to tooth extraction, and make appropriate regulation of systemic diseases, etc. The details are as follows. 1. Preoperative examination and evaluation: before tooth extraction, the patient’s oral and maxillofacial past medical history, local medical conditions, systemic conditions and other relevant information should be fully understood. 2. Excluding contraindications to tooth extraction: for example, patients with heart disease, hypertension, hematopoietic system diseases, diabetes, hyperthyroidism, renal disease, hepatitis, pregnancy, menstruation, acute infections, malignant tumors, long-term use of anticoagulant drugs, long-term adrenocorticotropic hormone therapy need to pay attention to their own conditions. Certain diseases after comprehensive treatment, under certain monitoring conditions, feasible tooth extraction. 3. Appropriate regulation of systemic diseases: patients with systemic diseases should be operated with the participation of internal medicine doctors, and the blood pressure and heart rate should be temporarily adjusted before the start of the operation.