Common causes of red and engorged gums include gingivitis, periodontitis, foreign body irritation, and periodontal abscess. 1. Gingivitis: plaque, tartar and other causes may cause gingivitis, resulting in red, congested, swollen and painful gums. 2. Periodontitis: Tartar, traumatic bite and other causes may cause periodontitis, resulting in bad breath, bleeding gums, swollen gums and other symptoms. 3. Foreign body irritation: If the gums in the mouth are pierced by hard food, or a fishbone is stuck in the gums, it may also cause redness and congestion of the gums. 4. Periodontal abscess: Acute periodontal abscess has a sudden onset, the gums form an oval or hemispherical swelling protrusion, the gums are red, edematous, and the surface is shiny. Gums redness and congestion may also be caused by other reasons, should go to the hospital in time to identify the cause and targeted treatment.