The main manifestations of the fierce period are: first, the baby will eat milk more frequently and the amount of milk will increase significantly under the premise of normal stool; second, the baby will wake up often in the night. The baby needs more nutrition in the long term, so he or she will often feel hungry and wake up at night to look for food because of hunger. Third, the baby is irritable and sleeps with night sweats. The baby’s demand for calcium is very high, there will be obvious calcium deficiency performance, will often shake his head, sweating more stimulation body skin itching, will cause emotional irritability.