Mucous cysts are found on the ventral side of the lower lip and the tip of the tongue. The cysts are located in the submucosa, and the surface is only covered with a thin layer of mucosa, so they appear as translucent, light blue vesicles, resembling blisters. The cysts are easily ruptured by bites, and the cysts disappear after the flow of egg-white clear and thick liquid. After the rupture heals, it is filled with mucus again and forms a cyst again. Broadly speaking, mucous cysts include minor salivary gland mucous cysts and sublingual gland cysts, which are the more common salivary adenoma-like lesions. Parotid cysts are divided into two main categories: retained and congenital, the former being rare. Benign hypertrophy of the salivary gland, also known as salivary gland enlargement or degenerative salivary enlargement, is a non-neoplastic, non-inflammatory, chronic, recurrent, painless enlargement of the salivary gland. Therefore, the prevention of this disease is mainly to avoid injury and maintain oral hygiene. The treatment of this disease is better with surgery, which should remove the gland of onset at the same time, because the cause of its onset is the damage or obstruction of the glandular ducts, and if there are damaged glands left after surgery, it is inevitable that salivary retention will occur again and the cyst will recur.