If the baby does not improve after four consecutive days of fever, further examination should be done to avoid more serious diseases such as pneumonia and encephalitis. You can first test the blood routine, C-reactive protein, respiratory pathogens, and do chest CT to clarify whether there are lung infections and bacterial and viral infections, because the cause of fever is mainly infectious diseases, so the causative pathogens should be found and treated symptomatically This is easier to cure. If the fever is caused by bacterial inflammation, it can be treated with broad-spectrum antibiotics, such as anti-inflammatory drugs like cephalosporins, which are very effective for bacterial inflammation. If it is due to a virus, you can use antiviral drugs such as ribavirin for about three days of continuous treatment, and take intravenous drip method of administration, which can effectively control the disease, to hurry up the treatment, to avoid delay.