Early pediatric respiratory infections are 80% viral, but later, especially in small infants with sputum, they tend to mix with bacterial infections. Older children with cold and fever basically do not need antibiotics if the laboratory tests are normal. Young children need to apply antibiotics according to the actual situation, and most of them also do not need to apply antibiotics. However, newborns and small infants with bacterial infections based should be treated actively without delay. When to use can not be summarized in one or two sentences, you can pay attention to the following indicators when abnormal: 1, white blood cells by age characteristics: adults: 4 to 10 × 10 of 9 times / L (4000-10000/mm3). Neonates: 15 to 20 × 10 of 9 / L [clinical significance], one year old leukocytes about 10,000, lymphocytes and neutrophils 6 days, 6 years have crossed. 6 days ago, 6 years after the neutrophil ratio is greater than 50%, close to adults. Pathological leukocyte increase is mostly seen in acute septic infection, uremia, leukemia, tissue injury, acute bleeding, etc. In some cases normal or reduced leukocytes also have the presence of infection, such as newborns below 4000 is one of the indicators of blood infection. 2, CRP, calcitoninogen is elevated, blood sedimentation is significantly increased, and anti-O is elevated. 3, bacteriological culture, quantitative antibodies to Mycoplasma pneumoniae and Chlamydia. 4.Blood smear, bone marrow picture with infection. 5, Although the laboratory tests are normal but there is a clear history or signs of infection.