If a newborn baby has a fever of 38.5 to 39.8℃ or higher, combined with restlessness, crying, flushed skin, dry mouth and lips, weight loss, and reduced urine output, but otherwise in good condition and without symptoms of infection and poisoning, it is medically called “neonatal dehydration fever”. The incidence of neonatal dehydration fever is higher in dry and hot weather seasons, and artificially creating a hot environment for children can also cause dehydration fever. Neonatal dehydration fever is mainly caused by the lack of water in the body of the newborn and causes fever. The main reasons are: 1, insufficient water: after birth, newborns lose a considerable amount of water through breathing, skin evaporation, excretion of urine and feces, and 3 to 4 days after birth, breast milk secretion is less, if not pay attention to supplementation will cause insufficient water in the body. 2, the ambient temperature is too high: parents fear that the newborn baby is cold, wrapped too tightly, excessive warmth, so that its body temperature rises, breathing increases, the skin evaporates more water, can also be dehydrated. In the above case, the newborn evaporates more water than sodium loss, the serum sodium increases, and the serum protein can also increase, which will lead to the occurrence of dehydration fever in newborns.