Swollen and painful gums and bleeding may be caused by the following reasons. 1. periodontal disease. If there is a large amount of calculus and plaque around the periodontium, it is easy to stimulate the gums to appear bleeding. When the lesion is more serious, it is easy to appear periodontal abscess, the gums will appear swollen and painful, and it will cause fever, then anti-inflammatory treatment should be carried out. If there is an inflammatory bulge, in which case there is a fluctuating sensation, incision and drainage can be performed. 2. there is inflammation in the apical part of the tooth, and a fistula of the gums appears, and this fistula will show slight bleeding, and there may be a small packet, and root canal treatment is generally recommended, and oral anti-inflammatory medication is also required. 3. caused by a pericoronal abscess of the wisdom tooth, when there is a pericoronal abscess, there is also a phenomenon of pus in the gums, and this 4, there may also be a hemangioma, and this situation generally requires surgical treatment.