The causes of high white blood cells in newborns include the following: first, a significantly high white blood cell count due to physiological factors. Physiological elevation of white blood cells can occur if the newborn has physiological vomiting, or if there is cold stimulation. After the newborn’s vomiting stops or is kept warm, the white blood cells will slowly return to normal and parents need not be particularly concerned. Secondly, leukocyte elevation is caused by severe bacterial infection. If a newborn has a severe bacterial infection, it can cause a significantly high white blood cell count. This is due to the fact that white blood cells have an obvious role in phagocytosis of bacteria, often with symptoms such as lethargy and fever. In this case, cephalosporins need to be applied promptly to fight bacterial infections.