Why is a three-month-old baby drooling? Baby drooling is commonly known as drooling, and it is mostly a normal physiological phenomenon. Related articles: What should I do if my baby has a cold, cough and runny nose? A normal adult secretes approximately 1000~1500mL of saliva throughout the day and night. However, so much saliva is almost completely swallowed by us unconsciously, so there is no saliva flowing out. Newborn baby…