Pus in the gums may be caused by periodontitis or septic periapical inflammation, and the treatments are periodontal treatment and root canal treatment, as follows. 1. Periodontitis: Periodontal abscess may appear when the disease progresses to the advanced stage, which requires periodontal treatment, including supragingival scaling and subgingival scraping, etc., to remove the plaque and tartar on and under the gingiva and the local irritants, and rinse the periodontal pockets in order to control the inflammation. 2. Purulent periapical inflammation: the pus from the root tip can be discharged from the gingival sulcus or periodontal pocket through the periodontal membrane. Gum symptoms can be relieved by eliminating the inflammation in the root canal and periapical area through root canal treatment. There may be other reasons for pus in the gums, so it is recommended to go to the hospital in time to receive early treatment.