The baby has been drooling usually and salivary gland secretion increase, swallowing function is not well developed and other physiological reasons, and the oral cavity and other pathological reasons have a relationship. 1. physiological reasons: in the baby’s growth salivary glands more and more mature, or the baby long teeth and other circumstances will lead to increased secretion of the salivary glands, and at this time the baby’s swallowing function is not yet well developed, may lead to the baby has been drooling, which is a normal physiological situation, parents do not have to worry too much. 2. Pathological reasons: the baby has been drooling may also be due to oral ulcers, herpes and other conditions that lead to saliva due to the inability to swallow normally and constantly out of the situation. There may be other reasons why your baby drools all the time, so it is recommended that you go to the hospital in time to get a clear picture of the cause of the problem under the guidance of your doctor.