Babies drool for the following reasons, one, salivary gland development, the baby to 3-4 months, the salivary glands began to develop, the amount of saliva increased, but the baby’s mouth shallow, can not retain too much saliva, coupled with the baby’s ability to swallow is not enough, there will be drooling situation. Second, teething, baby teething period, the gum tissue of mild swelling will stimulate the secretion of saliva, baby saliva will be particularly large. Third, the baby’s parotid glands are mechanically damaged, family members kissing the baby’s cheeks or pinching cheeks, easily causing mechanical damage to the parotid glands, resulting in more saliva secretion, the baby is easy to drool. Fourth, sick, baby oral inflammation, such as inflammation of the tongue, gum inflammation, inflammation of the oral mucosa, etc., inflammation stimulates the mouth will produce a lot of saliva.