Small babies often spit, mothers and fathers think that the baby is playful, in fact, not necessarily for this reason, the reason is diverse, divided into physiological and pathological reasons. Months old 3-4 months old baby, salivary glands began to develop, saliva secretion increased, but at this time the baby’s mouth is relatively shallow, swallowing function is not well developed, can not swallow in time, regulate the mouth too much saliva, so easy to appear drooling spit phenomenon. This is a physiological phenomenon that will disappear on its own with development. The cough reflex of newborns and small infants is immature, and the performance of pneumonia is atypical. Because the trachea of newborns and small infants is short and narrow and funnel-shaped, when exhaling, the gas in the lungs rushes out through the narrow trachea, rushing the phlegm in the trachea out of the mouth through the short respiratory tract and producing bubbles as the gas passes through the foul phlegm. Then, when children suffer from certain oral diseases such as stomatitis, tongue ulcers and herpes pharyngitis and pharyngitis, saliva cannot be swallowed properly and keeps flowing out. Many babies within 1 year old have the phenomenon of spitting, physiological will disappear naturally with the baby’s growth and development, while pathological need parents to take their children to the hospital for examination in a timely manner.