4 months baby crying at night, may be related to physiological factors and pathological factors (cold, colic, acute gastroenteritis). 1. Physiological factors, if the baby in the process of sleeping urine hungry or environmental temperature is too high or too low, too much light may affect the baby’s normal sleep, the symptoms of crying at night. If the daytime too excited or frightened may also lead to such symptoms. 2. Pathological factors, some of the baby disease may also lead to crying at night, such as colds, colic, acute gastroenteritis, etc., but also may be related to calcium deficiency. 4 months baby crying at night, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.