There are many reasons why a four-month-old baby has recurrent fever, the first and most common reason being the occurrence of an infection. The most common of these infections are respiratory infections or digestive infections. The child is small, it is easy to have a cold, resulting in upper respiratory tract infections, which can also lead to recurrent fever, accompanied by nasal congestion, runny nose, sore throat, the use of cold medicine for treatment, the effect is better, such as the An Er Ning granules. Secondly, if severe coughing, coughing or wheezing occurs, it is likely that bronchitis or pneumonia will occur, which is more serious and requires hospitalization, and appropriate antibiotics or antiviral drugs need to be selected for intravenous drip treatment according to the type of infection. If digestive symptoms occur, it is likely that the child has diarrhea, which is more common in rotavirus infections and often results in egg-flower-like stools.