Under normal circumstances, bleeding will stop in about 15~30 minutes after tooth extraction. It is abnormal to bleed five hours after tooth extraction, which is usually caused by local factors, improper care and systemic factors. 1. Local factors: Bleeding may be caused by residual inflammatory granulation tissue in the alveolar fossa, soft tissue tear, rupture of small blood vessels in the alveolar space, fracture of the alveolar process, etc. 2. Improper care: it may be the premature removal of compression cotton rolls or improper protection of blood clot shedding leading to postoperative bleeding. 3. Systemic factors: if there is uncontrolled hypertension, hematopoietic system diseases, diabetes, hepatitis, long-term use of anticoagulant drugs or patients in the menstrual period, postoperative bleeding symptoms may occur. Bleeding five hours after tooth extraction may have other reasons, it is recommended to go to the hospital in a timely manner.