A large amount of saliva secretion under the tongue may be caused by food irritation, oral inflammation or caused by imperfect brain development, which needs to be checked in the hospital. 1. Food stimulation. Seeing food or acidic substances in daily life will trigger salivation, and the sublingual gland secretes saliva in large quantities. 2. Oral inflammation. Inflammation of the submandibular gland or sublingual gland, pericoronitis or periapical inflammation of the wisdom teeth can also trigger a large amount of saliva secretion due to inflammatory stimuli. 3. Imperfect brain development. If the nerve center that controls the secretion of the submandibular gland and other glands is not well developed, saliva may be secreted excessively. It is recommended to go to the hospital to improve the oral clinical examination to determine the cause of saliva secretion under the tongue.