Three-year-old children with high fever can be seen in respiratory diseases, gastrointestinal diseases or hematologic diseases, etc., whether the need for injections need to be combined with the condition of the physician to decide, such as influenza children generally do not intramuscular injection, the need for oral treatment of oseltamivir phosphate. 1. Respiratory disease: three-year-old children with high fever caused by influenza, most need oral oseltamivir phosphate treatment, generally without myeloablative therapy. For children with acute suppurative tonsils and increased infection indicators, when oral antibacterial drugs (e.g., cefaclor) are ineffective, cefamandole can be evaluated by a physician for intramuscular anti-infective treatment. 2. Gastrointestinal diseases: such as acute gastroenteritis, clinical fever, vomiting or diarrhea symptoms, for such children if the condition is serious (such as dehydration, repeated body temperature and vomiting severe) generally need intravenous fluid therapy, intramuscular injection of drugs may be ineffective. 3. Urinary tract infection: high fever can also occur, may be accompanied by urinary tract irritation signs, such as urinary frequency, painful urination, etc., for such children if the duration of the disease is short, the infection index is not serious, can be the first oral antibacterial drugs, such as cefaclor treatment, without the need for intramuscular injection drug treatment. 4. Other: such as Kawasaki disease, for such children can appear high fever, often accompanied by skin rash, chapped lips and other symptoms, after the diagnosis is clear, generally do not intramuscular injection treatment, need to use intravenous gammaglobulin and oral aspirin and other drugs. These drugs should be used under the guidance of a physician. When a child develops a high fever, it is recommended that he or she be seen by a specialist to determine treatment.