Drooling in infants is not necessarily a normal condition, but can also be caused by disease. First of all, if the baby is in the eruption stage, the bottom of the mouth is also shallow at this time, which can cause drooling in babies. The infant has no other symptoms of discomfort, no obvious crying or restlessness, and a normal appetite for food. Secondly, if the infant not only has drooling, but also refuses to eat, eats milk poorly, or even has a fever, and after checking the infant’s body, he/she sees herpes in the mouth. This time is mostly due to inflammation of the mouth.