The baby has been crying, may be due to external discomfort factors, digestive flatulence, intestinal colic, other diseases. 1. External discomfort factors: when the baby exists in the outside world or their own discomfort factors, easy to feel insecure or directly lead to the baby’s physical discomfort, such as too cold, too hot, hungry, uncomfortable way to embrace, etc. may lead to its crying. 2. Digestive tract flatulence: due to feeding burp incomplete, indigestion and other factors, can make the baby’s digestive tract flatulence, thus appearing crying performance. 3. Colic: it is easy to occur in babies less than 3 months old, which can be caused by imperfect development of the digestive system, imbalance of healthy flora in the digestive tract, and other factors, which will make babies cry frequently, for a long period of time and violently. 4. other diseases: such as acute gastroenteritis, eczema, calcium deficiency, vitamin D deficiency, etc., can cause the baby has been crying. Not full-term baby has been crying, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.