A white substance after wisdom tooth extraction can be caused by food debris, false membrane or infection. 1. Food debris: After wisdom teeth extraction, deep cavities will be formed, and food debris is easy to accumulate in the extraction sockets to form a white substance when eating; generally no special treatment is needed, and routine oral care can be done. 2. Pseudomembrane: after wisdom teeth extraction, when the wound starts to heal, the blood will be mechanized or mucosal tissue proliferation, white material will appear; again, no special treatment is needed, and attention must be paid to not be able to remove it by gargling, etc., in order to prevent affecting the healing of the wound. 3. Infection: if the wound is infected, there will be white purulent secretion and accompanied by wound swelling and pain and other symptoms; it is recommended to consult a doctor for anti-inflammatory and anti-oedema treatments, such as scratching and rinsing of wounds to remove inflammatory substances, and taking anti-inflammatory drugs (such as amoxicillin, metronidazole, etc.) as prescribed by the doctor in order to control the inflammation. White material after wisdom teeth extraction, it is recommended to consult a doctor for a clear diagnosis and symptomatic treatment to avoid delaying the condition.