There are two common clinical cases of sublingual frenulum enlargement: 1) intraoral type of sublingual cyst; 2) swelling of the lower part of the tongue due to infection of the floor of the mouth. For the intraoral type of sublingual cysts, the swelling is unilateral and obvious, and the texture may look bluish and soft to the touch, the patient has no obvious pain and no systemic symptoms, the sublingual gland needs to be surgically removed together with the cyst, and the disease can be cured. There is also an infection in the sublingual area of the floor of the mouth, which may cause a bulge in the entire lower part of the tongue, with obvious pain and fever, and local incision and drainage can be considered, as well as systemic application of anti-inflammatory drugs to control the infection.