Sudden fever in babies is mostly caused by viral or bacterial infections, which can be treated by physical cooling, taking antipyretic drugs, rehydrating fluids, and actively treating the primary disease. 1. Physical cooling: For babies with good mental state and body temperature not more than 38.5℃, you can use a warm towel to wipe the baby’s armpits, groin, neck, elbow, and other large blood vessels throughout the body, to help the baby dissipate heat. 2. Taking antipyretic drugs: For babies with fever over 38.5 ℃, they can be treated with antipyretic drugs under the guidance of a doctor, and commonly used antipyretic drugs include ibuprofen suspension, acetaminophen granules, and so on. 3. Rehydration therapy: because the baby fever, not obvious water loss will increase significantly, then you can give the baby intravenous rehydration or to be oral rehydration salts for rehydration, on the one hand, to help replenish the loss of water, on the other hand, the supplemental room temperature liquid through the urine can take away part of the heat. 4. actively treat the primary disease: if you consider bacterial infection, you can follow the doctor’s instructions to be antibiotic anti-infection, such as cefaclor, amoxicillin, azithromycin and other anti-infective, such as viral infection, you can follow the doctor’s instructions to be rehydration and other symptomatic supportive treatment. The above drugs can lead to nausea, vomiting, rash, liver function impairment and other adverse reactions, the baby in taking these drugs for treatment, must be strictly in accordance with the doctor’s instructions under the guidance of the doctor. Baby sudden fever may also be related to other causes, such as Kawasaki disease, leukemia, etc., in addition to fever parents should also pay attention to observe whether there are other uncomfortable symptoms, it is recommended to consult a doctor in a timely manner, in order to clarify the cause of the disease, standardized treatment.