It is very common for babies to drool in their sleep, especially for babies around six months old. Mainly due to this period of the baby salivary gland secretion is very strong, coupled with the mouth of the mouth bottom is very shallow, sleep saliva will not be swallowed will lead to drooling. There are many reasons why babies sleep drooling, babies in the period of milk teeth eruption, teeth want to break through the gum growth will make the gums painful and itchy, in the role of the nerve, so that the baby saliva secretion increased, and the baby mouth is small, and will not adjust their own swallowing, making the phenomenon of drooling frequent. In addition, and the mental state, if the baby is too nervous during the day too tired, sleep at night when the baby’s nerve function regulation is affected to a certain extent, there will be drooling phenomenon. Some may also be digestive factors, such as indigestion, may also be prone to drooling during sleep, or some teeth grinding, these are physiological drooling. Sometimes drooling can also be caused by certain diseases, such as mouth ulcers, pharyngitis, intellectual disability and other problems. When a baby drools, parents should promptly wipe the baby, pay attention to the skin around the baby’s mouth to avoid eczema, but also promptly observe the baby, once the discovery of abnormalities promptly take the baby to the doctor, so as not to delay the disease.