The possible causes of headache and vomiting in a twelve-year-old child are intracranial infection, epilepsy, trauma, motion sickness, etc. 1. Intracranial infections: such as viral encephalitis, tuberculous meningitis, suppurative meningitis, etc., there may be headache and vomiting symptoms, and there may be a consciousness disorder, the need for timely hospitalization to improve the cranial magnetic resonance or cranial CT, lumbar puncture of cerebrospinal fluid and other tests can be a clear diagnosis. 2. Epilepsy: Epileptic seizures are divided into partial and generalized seizures, and headache and vomiting may occur in generalized seizures. It is recommended to consult a doctor in time to improve the electroencephalography and make a clear diagnosis by combining clinical symptoms. 3. other: for example, trauma caused by craniocerebral injury brain hernia may also appear headache and vomiting, need to consult a doctor; children may also appear dizziness, vomiting and so on, usually will be improved by themselves. A twelve-year-old child with headache and vomiting needs to be closely observed and, if necessary, examined and treated by a doctor.