A high fever at night and normal during the day in a baby suggests that the infection is not under control. Because fever is caused by bacteria, virus, mycoplasma and these toxins stimulation, so only after the infection pathogens are completely killed or controlled, can the body temperature drop to normal, no matter if the fever is during the day or at night, it is not normal. Therefore, it is necessary to check the blood routine to see which kind of pathogenic bacteria is infected. If it is a bacterial infection, cephalosporin anti-inflammatory drugs are needed; if it is a viral infection, there is no special medicine; if it is a mycoplasma infection, azithromycin or erythromycin can be applied. If the medication is still not fully restored to normal after 3 days of oral administration, it is necessary to re-lab test to see if there is bronchitis, pneumonia, neurological infection, etc.