Often patients who need tooth extraction go to the hospital to have their teeth extracted, but after the physician’s examination, he or she tells the patient that the tooth cannot be extracted under the present circumstances, which causes a lot of time and energy to be lost. Although tooth extraction is the most common minor surgery in stomatology, there are strict indications for tooth extraction, if the tooth is extracted under unsuitable conditions, it will often bring undue loss and pain, and in severe cases, it will also be a crisis of life. Therefore, before tooth extraction, you should make the following preparations to understand what circumstances are not suitable for tooth extraction? 1, before the extraction of teeth should be well prepared for the mind, keep the mood calm, eliminate the fear of tooth extraction, nervousness and fear of psychology, cooperate with the doctor in the process of tooth extraction. 2, before the extraction of teeth should have a good sleep and rest, do not go directly to the extraction of teeth in the case of tiredness, fatigue, sleep deprivation, in order to avoid reducing the tolerance of the extraction surgery. When the general health condition is poor, tooth extraction should be postponed. 3, before the extraction of teeth should eat properly, do not pull teeth on an empty stomach, in order to avoid hypoglycemic shock or fainting. 4.The doctor should know your past medical history 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, pulmonary tuberculosis, diabetes mellitus, liver and kidney diseases, mental diseases, malignant tumors and other systemic medical history, tooth extraction may produce Serious complications, even life-threatening. Therefore, teeth should be extracted only after effective control. 5, female menstruation, pregnancy (especially in the first three months of pregnancy and the second three months) should avoid tooth extraction; taking contraceptive pills during the general should not be extracted. 6, cold, after strenuous exercise, after drinking alcohol should not be extracted. 7, acute infectious diseases, acute inflammation in the oral cavity should not be extracted. 8, long-term use of anticoagulant drugs, such as aspirin, Favalin, 1 week before extraction need to stop; head and neck malignant tumors after radiotherapy 3 ~ 5 years should not be extracted.