There are often many patients who need to have their teeth extracted and have come to the hospital several times to ask for extraction, only to be told by the physician after examination that the patient cannot have the tooth extracted under the present circumstances, delaying a lot of time and energy. Although tooth extraction is the most common minor surgery in dentistry, there are strict indications for tooth extraction. If a tooth is extracted under unsuitable conditions, it will often bring undue loss and pain, and in severe cases, it will also be life-threatening. Therefore, before tooth extraction, you should make the following preparations and understand under which circumstances is tooth extraction unsuitable? 1. Before tooth extraction, you should be fully prepared mentally, keep a calm mood, eliminate the fear, tension and dread of tooth extraction and cooperate with the doctor in the process of tooth extraction. 2. Have a good sleep and rest before tooth extraction, do not go to tooth extraction directly under the condition of tiredness, fatigue and lack of sleep to avoid reducing the tolerance to tooth extraction surgery. When the whole body health is poor, tooth extraction should be suspended. 3. Before tooth extraction, you should eat properly and do not extract teeth on an empty stomach to avoid hypoglycemic shock or fainting. 4. Before tooth extraction, you must tell the doctor about your health condition, especially the history of systemic diseases, such as cardiovascular system diseases (hypertension, coronary heart disease, etc.), hematological system diseases (hemophilia, primary thrombocytopenic purpura, leukemia, etc.), hyperthyroidism, tuberculosis, diabetes, liver and kidney diseases, mental diseases, malignant tumor and other systemic diseases, where tooth extraction may produce serious complications and even endanger life. Therefore, tooth extraction should be done only after effective control. 5. Dental extraction should be avoided during menstruation and pregnancy (especially during the first and second trimesters of pregnancy); dental extraction is also generally not advisable during contraceptive pill taking. 6. Tooth extraction is not recommended after cold, strenuous exercise and alcohol consumption. 7. Tooth extraction is not recommended when there is acute infectious disease or acute inflammation in the mouth. 8. Long-term use of anticoagulant drugs, such as aspirin and favalin, should be stopped for 1 week before tooth extraction; tooth extraction should not be performed within 3-5 years after radiotherapy for malignant tumors of the head and neck.