Headache and nausea in a 14-year-old child may be caused by upper respiratory tract infection, purulent meningitis and head trauma. 1. Upper respiratory tract infection: Upper respiratory tract infection can cause symptoms other than respiratory tract because infections such as bacteria or viruses cause bacteremia and the release of inflammatory factors, which can cause systemic symptoms such as headache, nausea, vomiting and so on. 2. Septic meningitis: Septic meningitis can lead to increased inflammatory exudation, causing meningeal irritation and increased intracranial pressure, which can trigger reactions such as headache, nausea and vomiting. Untreated, there will be neurological damage, which can be life-threatening in severe cases. 3. Head trauma: head trauma can cause head soft tissue and skull injury, the formation of hematoma, can cause headache, nausea, vomiting and other manifestations. 14-year-old child headache and nausea, may also be sinusitis, intracranial tumors and other causes, the child should go to the hospital in a timely manner to improve the examination, to clarify the cause of the timely treatment and treatment.