Swelling at the root of tongue may be cyst of sublingual gland, thyroglossal duct cyst or carcinoma of the root of tongue, among which cyst of sublingual gland and thyroglossal duct cyst are not carcinoma, and carcinoma of the root of tongue belongs to the category of cancer, as follows. 1. Sublingual gland cyst: often caused by the extravasation of mucus after rupture of the excretory duct of sublingual gland. The texture is soft and usually painless. Larger cysts will lift up the tongue body and form “heavy tongue”. The common treatment is excision of the sublingual gland, which has a good prognosis. 2. Thyroglossal cyst: It is a congenital disease, mostly caused by the thyroglossal duct not degenerated or incomplete degeneration during embryonic period. Larger cysts may cause pain or difficulty in swallowing. Surgical excision is the main treatment and the overall prognosis is good. 3. Carcinoma of the root of the tongue: it occurs with the chronic irritation existing in the oral cavity for a long time. It manifests as foreign body sensation at the root of tongue and dysphagia and pain. Lymph node metastasis can occur in early stage and lung metastasis may occur in late stage. The treatment is a comprehensive treatment based on surgical treatment. There may be other reasons for the swelling at the base of the tongue, and it is recommended to go to the hospital in time.