There are many reasons for a white pus on the gums, including acute periodontal abscess, gingivitis, apical periodontitis, etc., and it is necessary to consult a doctor to find out the specific cause. 1. Acute periodontal abscess: bacterial infection in the gums to form a white pus, pus around the loose tissue will form periodontal pockets, so that the pus can not be discharged. If it is not treated in time, it will turn into chronic periodontal abscess in the later stage of development. 2. Gingivitis: Gums are red and swollen, pain is obvious, there is a white pus, can also be considered gingivitis. Gingivitis is mostly caused by plaque, pay attention to oral hygiene and cleanliness, remove plaque can make the inflammation reversed. 3. Periapical periodontitis: commonly caused by bacterial infection, such as dental caries and other failure to cure, infection of the root tip, or dental trauma and other injuries to the apical tissues, will be manifested in the damaged tooth roots corresponding to the location of the gingival tissues appeared white pustules, pain when moving, can be puncture pus drainage, anti-inflammatory treatment.