4-year-old baby fever and headache should be considered caused by colds, older babies with common colds can also have a headache, headache is generally less intense, if the fever and headache is obvious, limb aches and pains should also pay attention to the possibility of influenza A, B, we have to go to the hospital to do laboratory tests to do the screening of influenza viruses, but also to do the routine blood C-reactive protein test. If the fever and headache are accompanied by severe vomiting, especially projectile vomiting, poor spirit, but also pay attention to the possibility of intracranial infection, viral infections can cause viral encephalitis, meningitis, bacterial infections caused by septic meningoencephalitis, and other infections may lead to intracranial infections, which need to be caused by the parents pay great attention to the situation. When headache and fever occur, measures should be taken to lower the temperature and alleviate the discomfort. Usually, when the fever is high, antipyretics such as ibuprofen should be taken, and antelope horn granules and other heat-reducing and detoxifying medicines can be taken to alleviate the symptoms.