Swollen gums with pus, caused by apical periodontitis need root canal treatment, periodontal inflammation caused by the need for periodontal treatment. 1. Apical periodontitis: Inflammation of the pulp is not treated in time, and the inflammation spreads to the tissues around the root tip, resulting in apical periodontitis, which causes swelling of the gums, abscesses in the corresponding apical area, and purulent secretions overflow, which requires perfect root canal treatment of the tooth to remove the foci, in order to restore the inflammation. 2. Periodontal inflammation: chronic invasive inflammation that occurs in the periodontal tissues, can lead to alveolar bone atrophy, deep periodontal pockets, pocket bacterial infection and fermentation, swelling of the gums, pus, the need for periodontal treatment of the teeth, such as scaling, scraping, periodontal pockets in the bureau of the local medicine, periodontal surgical treatment and other measures, if necessary. Swollen gums with pus need to seek medical attention in a timely manner, under the guidance of the doctor for examination and treatment, so as not to delay the condition.