Patients who smoke in the afternoon after tooth extraction can closely observe the trauma for bleeding, because the adverse consequence of smoking after tooth extraction is mainly to cause trauma bleeding, if there is no bleeding generally do not need to worry too much, but do not smoke again. Smoking is generally not recommended for 2-3 days after tooth extraction. If the tar and nicotine in the smoke penetrate into the wound, it will affect the formation of blood clot and dissolve the small blood clots that have been formed, which will lead to blood leakage from the wound. For more traumatic extractions, premature smoking may create a negative pressure environment in the mouth, resulting in a greater risk of clot dislodgement and bleeding from the wound. Certain substances in the smoke will reduce the supply of nutrients and oxygen to the traumatized tissues, plus the nicotine and carbon monoxide in the smoke itself has the effect of indirectly inducing vasospasm, which further reduces the blood supply to the tissues around the tooth extraction wound, thus localizing the nutrients and oxygen to the wound accordingly, and delaying the healing of the wound. If a patient has just had a tooth extracted, it is recommended that he or she should not smoke, and if failure to comply with medical advice results in more than just bleeding and infection of the wound, it is recommended that he or she seek medical attention in a timely manner.