Babies crying all the time may be caused by physiological factors, pathological factors such as vitamin D deficiency, intestinal cramps and other factors. 1. Physiological factors: the room temperature is too high or too low, the baby is too hungry, was frightened, will cause the baby to cry, after eliminating the above triggers, the baby crying phenomenon will stop by itself. 2. Pathological factors: for example, vitamin D deficiency, the lack of vitamin D in the body of infants, may lead to a decrease in blood calcium levels, will often appear crying, easy to startle the phenomenon, may also be accompanied by difficulty in falling asleep, occipital baldness and other abnormal manifestations. In addition, such as cramps and other diseases may also cause abdominal discomfort resulting in infants crying, may also be accompanied by nausea and vomiting and other symptoms. Clinically, there are many reasons for babies to cry all the time, such as intussusception and other diseases can also lead to babies paroxysmal crying, if the baby is always crying or can not be soothed, you can take the child to the doctor for examination, and follow the doctor’s instructions for treatment.