Leukocytes are a very important type of immune cells in the human body, and they play a very important role in the immune system of the body. The causes of high white blood cells in babies are usually due to various factors such as inflammatory infections, bleeding, poisoning, leukemia, etc. The baby’s immune system itself is not fully developed, so it is susceptible to bacterial infections, which may be related to diseases such as upper respiratory tract infections, pneumonia, digestive tract infections, urinary tract infections, etc. Therefore, routine blood tests can be done when the baby has a fever, runny nose, cough, diarrhea, frequent urination, and excessive urination, and may find elevated white blood cells, making the child have a bacterial infection. If the baby has bleeding from internal organs, it can also cause elevated white blood cells, which are commonly caused by traumatic bleeding and hemolytic diseases. Food poisoning is also a cause of elevated white blood cells, such as when the baby drinks expired milk powder or when the mother eats food that contains toxicity, and then the baby drinks breast milk. Some of the initial symptoms of leukemia are a sharp increase in white blood cells, which can be ridiculously high, and other symptoms, such as bleeding, anemia, and fever. If your baby has a routine blood test and is found to have elevated white blood cells, you need to identify the cause of the disease and then provide targeted treatment. The level of white blood cells is also an important indicator to determine whether the inflammation is under control, so it also needs to be reviewed regularly.