A soft bag on the gums may be caused by apical periodontitis, periodontal abscess, gingival hyperplasia and so on. 1. Periapical inflammation: It is mainly caused by the infected material in the root canal penetrating from the apical foramen, causing inflammatory reaction of the periapical tissues. It usually manifests as pain in the affected tooth and its surrounding tissues, and sometimes there can be discomfort when chewing and the symptom of a soft bag in the gums. 2. Periodontal abscess: patients may not pay attention to oral hygiene and improper diet, resulting in inflammation of the gums and surrounding tissues, long-term inflammation will lead to periodontal abscess. It is usually characterized by red and swollen gums with pus, loose teeth and severe pain. 3. Gingival hyperplasia: patients may have gingival hyperplasia because the gums will grow to the position of the missing teeth after the teeth are missing. Early on, the gums may be shiny, red, swollen and pus-filled. If the gums rise a soft bag, it is recommended to go to the hospital in time, under the guidance of the doctor, to identify the cause of the disease, under the guidance of the doctor treatment.