The common causes of headache and vomiting in 12-year-old children are as follows: First, intracranial infectious diseases, including viral encephalitis, tuberculous meningitis, septic meningitis, and rare diseases such as syphilis and intracranial infection caused by HIV infection, etc. In addition to headache, nausea and vomiting, they are mostly accompanied by fever and changes in mental status, such as confusion, lethargy and coma. Some of them are accompanied by seizures and hemiplegia, and the diagnosis can be made by cranial magnetic resonance or cranial CT or lumbar puncture cerebrospinal fluid examination. Secondly, migraine, especially in female children, can be accompanied by blurred vision, photophobia and phonophobia in addition to headache and vomiting, and mostly improves on its own after rest. Third, epilepsy, some children with epilepsy will show headache and vomiting before and after seizure or at the time of seizure, some with grand mal seizure, some with psychomotor seizure, medical history, EEG, cranial MRI and other examinations can make a clear diagnosis. Fourth, other, seen in mild carbon monoxide poisoning, heat stroke, sinusitis, gastrointestinal flu, etc.