If the cotton roll and gauze of the extraction socket are not tightly bitten within half an hour after tooth extraction, and if the patient rinses his mouth and brushes his teeth, drinks hot water and hot meal, chews with the affected side, repeatedly licks and sucks the extraction socket and repeatedly spits, the blood clot covering the extraction socket may be dislodged, causing pain and bleeding in the extraction socket within 24 hours. Complex operation during tooth extraction, chronic inflammation of the affected tooth, partial gum alveolar bone damage, blood disease and other systemic diseases may cause pain and bleeding. Light pain and a small amount of blood-like sputum after tooth extraction are normal. Severe pain and obvious bleeding should be brought to the emergency dental room to deal with the extraction sockets immediately.