The sublingual glands are located in the submucosa of the floor of the mouth, one on each side, and secrete mucus that is transported to the oral cavity through ducts. Sublingual cysts can be classified as extravasated or retained. Extravasated cysts can be caused by rupture of the ducts and leakage of mucus into the tissue spaces. Retained cysts are mainly caused by partial obstruction of the ducts, resulting in poor mucus drainage, which can be caused by tiny stones, bending of the ducts, etc. Tiny food residues can enter the duct and thus form stones in the center. Usually, one should eat less food that can easily form powder into the mouth, such as cookies and knocking melon seeds.