The swelling of the lips is caused by the following reasons: 1. Swelling of the lips caused by trauma, when the teeth bump into the lips will make the lips appear red and swollen, accompanied by bleeding and oozing, usually heal themselves by maintaining oral hygiene. 2. Swelling caused by local inflammation, including acute inflammation of the oral and maxillofacial periodontium, apical abscess can spread to the periodontium and around the lips, causing periodontal gap, submaxillary gap infection involving the Red and swollen lips, need to go to the hospital to clarify the cause of symptomatic treatment. 3, allergic inflammatory reaction, taking or drinking, as well as contact with the body allergens, resulting in systemic allergic reactions, causing swelling of the lips, accompanied by facial itching, rash, etc.. In such cases, anti-allergic treatment is needed, such as cetirizine, loratadine or timely application of glucocorticoid anti-inflammatory and anti-allergic treatment at the hospital.