Common causes of fever in 0-3 months old infants include environmental factors, upper respiratory tract infections, etc. Parents can choose physical cooling, medication as well as massage under the guidance of the doctor for treatment. 1. Environmental factors: the environmental temperature is relatively high, the package is thicker, the baby’s skin heat dissipation is slower, will cause an increase in body temperature, this is mostly low fever, the baby is not uncomfortable performance. At this time, there is generally no need for medication, reduce the environmental temperature, unpacking, etc., the body temperature can be returned to normal. 2. Upper respiratory tract infection: infant resistance is weak, by the cold air stimulation or external infections such as easy to cause upper respiratory tract infection, thus appearing fever. Body temperature is lower than 38.5 degrees can be placed on the head antipyretic patch to lower the temperature, body temperature is higher than 38.5 degrees need to follow the doctor’s advice to take acetaminophen and other antipyretic drugs treatment. 0-3 months baby fever may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, give targeted treatment or treatment.