3-year-old baby suddenly fever 38 ℃, said the sore throat is common in respiratory tract infections, infectious mononucleosis and other conditions, the treatment needs to be decided according to the baby’s condition, such as acute suppurative tonsillitis need to be reasonable antipyretic, anti-infective treatment as appropriate. 1. respiratory tract infection: such as acute suppurative tonsillitis, the baby can appear fever, sore throat symptoms, physical examination can be seen pharyngeal congestion, tonsils enlarged, visible pus secretion. Such babies need reasonable treatment to reduce fever, such as the use of warm water wipes and other ways of physical cooling, and dynamic monitoring of body temperature, such as body temperature over 38.5 ℃ need to use acetaminophen and other antipyretic. The presence of bacterial infection requires the use of antibacterial drugs (such as amoxicillin, etc.) anti-infection treatment, and pay attention to drink more water. 2. Infectious mononucleosis: caused by EBV infection, the clinical manifestations are fever, pharyngitis and lymph node enlargement, some of them may have splenomegaly, and the examination of perfect heterogeneous lymphocytes can be seen to be elevated. Treatment requires antiviral therapy with acyclovir and reasonable cooling during the course of the disease, such as physical cooling or oral antipyretics (e.g., ibuprofen) to reduce fever. These medications should be used under the supervision of a physician, and it is recommended that the patient be actively consulted and treated by a specialist.