Newborn babies spit up white foam at the mouth is usually seen in respiratory tract infections. Because of their weak coughing ability, babies are usually lying down or lying down, so they cannot cough to get rid of phlegm like adults do, so they use foaming at the mouth to get rid of airway secretions. In addition, neonatal convulsions can also occur with loss of consciousness and foaming at the mouth. If a newborn has a large amount of foaming at the mouth, esophageal atresia may be considered. To sum up, there are many causes of foaming at the mouth in newborns, and they need to be diagnosed in the hospital and treated accordingly.