Swollen gums may be caused by chronic gingivitis, acute gingival papillitis, gingival lesions of leukemia, periodontitis and other diseases, as follows. 1. Chronic gingivitis: when suffering from chronic gingivitis, the gingival margin becomes thicker, the gingival papilla becomes rounded and hypertrophied, and the surface of the gingiva is bright when the inflammatory edema is obvious. 2. Acute gingivopapillitis: a single gingival papilla is red and swollen, with spontaneous distension and obvious tenderness, and locally visible irritants, such as filling body overhangs, fish spines, broken toothpicks and so on. 3. Gingival lesions in leukemia: enlarged gums, soft and fragile tissues or medium hardness, swelling is often mouth-wide, and the gums have obvious bleeding tendency. 4. Periodontitis: the gums are edematous and loose, there may be gum bleeding when brushing or eating, there is loss of attachment and alveolar bone resorption. There may be other reasons for swollen gums, it is recommended to go to the hospital in a timely manner, to clarify the cause of the disease for targeted treatment.