Post-extraction pus means that there is wound infection in the extraction area, which often occurs more than 3 days after extraction, with redness, swelling and pus overflowing from the local extraction wound, accompanied by bad taste or odor in the mouth. In this case, it is necessary to go to a professional dental institution as soon as possible, including local and systemic treatment, local can be used for incision and drainage of pus, and at the same time, can be sent to the pus bacteria culture combined with drug sensitivity test. If the causative organisms can be cultured, antibiotics can be applied according to the sensitivity test of the causative organisms, which is the best way to apply antibiotics. If conditions do not permit, systemic application of cephalosporin combined with metronidazole can be considered for systemic anti-inflammatory treatment. For localization, besides incision, local irrigation can also be considered, so that the pus can be adequately drained.