There are many causes of drooling in 2-year-old babies, and there are not 5 causes, and usually more than 5 causes. Common causes of drooling in 2-year-old babies, mainly including physiological salivation and pathological salivation, as follows: a. Physiological salivation: 1, weak swallowing ability: because the swallowing function of 2-year-old babies is not well developed, can not swallow the saliva secreted in time, there will be obvious drooling phenomenon; 2, teething: baby generally to 2-2.5 years old teeth will all erupt, so 2-year-old babies may Still in the teething period, teething baby, due to the eruption of teeth, teeth upward growth process will produce stimulation, resulting in a large amount of saliva secretion, will also appear drooling phenomenon; 3, food stimulation: when the baby sees the food you want to eat, will reflexively drool, or eat more acidic food, will also appear drooling phenomenon; 4, attention shifting: when the baby is more focused on one thing. For example, focus on playing with the toy in hand, or watching TV, may forget to swallow saliva, will appear drooling phenomenon. Second, pathological salivation: 1, oral diseases: such as oral ulcers, herpes gingivostomatitis, herpes pharyngitis and other oral inflammatory diseases, will stimulate the salivary glands to increase secretion, and can be accompanied by pain, affecting the baby’s swallowing function, the symptoms of drooling; 2, parotid gland injury: if the baby’s cheeks are often pinched and pressed, easy to make the parotid gland mechanical damage, will cause the secretion of saliva to increase, it will produce 3, respiratory tract inflammation: such as cold, tonsillitis, laryngitis and other diseases, the baby may have nasal congestion, swelling and pain in the throat and other uncomfortable symptoms, affecting the swallowing function, thus appearing drooling phenomenon; 4, neurological diseases: such as encephalitis, facial nerve palsy, cerebral palsy, etc., may cause damage to the nerves that govern the salivary glands and swallowing function, causing abnormal secretion of salivary glands and impaired swallowing function cause abnormal drooling phenomenon.