Biting cotton after tooth extraction is generally recommended to be removed after about half an hour, which can be extended appropriately if necessary, but preferably not more than one hour. After tooth extraction, the doctor will place a cotton ball or gauze in the extraction wound and ask the patient to bite tightly in order to achieve the role of pressure to stop bleeding and promote the formation of blood clots. It is generally recommended to bite the cotton ball for about half an hour, and after the doctor checks that there is no obvious bleeding, the cotton ball can be removed. But individual patients, if the extraction wound is large, etc., after half an hour there is still obvious bleeding, can be appropriate to extend the time to bite the cotton ball, but it is best not to exceed one hour, biting the cotton ball time is too long, will also affect the healing of the extraction wound. In addition, also pay attention to the extraction of teeth within 24 hours do not brush teeth and rinse mouth, extraction of teeth within 2 hours can not eat, to prevent blood clot shedding, which is not conducive to the healing of the extraction wound.