Infants always sticking out their tongues may be caused by physiological factors such as exuberant secretion of salivary glands or micturition period, or it may be related to pathological factors such as indigestion or oral ulcers, which are analyzed as follows: 1. Physiological factors: infants salivary gland secretion is more exuberant, will produce more saliva, in the immature development of swallowing function, saliva can not be swallowed in full, so it will be often drooling, so infants will stick out their tongues to lick the saliva around the mouth. In addition, if the infant has the above symptoms, he or she may have entered the micturition period, and sticking out his or her tongue is mainly for sensing things in the outside world. 2. Pathological factors: babies who usually have indigestion will also have the above symptoms, accompanied by nausea, vomiting and other adverse reactions; in addition, if you have mouth ulcers will also appear to stick out their tongues, and the amount of milk will be significantly reduced, and even involuntary shaking of the head. Babies often stick out their tongues may also have other reasons, it is recommended to go to the hospital in time for relevant examinations, clear causes and then actively treat the symptoms.