It may be normal for infants to spit all the time, but pathologic factors such as oral ulcers and pneumonia cannot be ruled out. 1. Normal condition: It is mostly due to the imperfect development of swallowing coordination ability of infants, salivary gland secretion is vigorous, saliva is more, which causes infants to spit all the time. 2. Mouth ulcers: If there are ulcers in the mouth, in order to relieve the pain, the infant will spit out the saliva, thus causing the infant to spit all the time. 3. Pneumonia: It may be due to the lack of warmth measures, resulting in infants being infected by bacteria and other pathogens, causing pneumonia, leading to increased respiratory secretion, saliva in the mouth will also increase, resulting in infants spitting all the time. Babies spit all the time, may also be other causes, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, give targeted treatment or standardized treatment.