Headache and nausea may be caused by epidemic cerebrospinal meningitis, hypertension, cerebral hemorrhage, cerebral infarction, migraine and other diseases. 1. Epidemic cerebrospinal meningitis: it is a purulent meningitis due to meningococcal infection, which mainly manifests as high fever, severe headache, nausea and vomiting. 2. Hypertension: when the systolic blood pressure is greater than or equal to 140 and the diastolic blood pressure is greater than or equal to 90, it is called hypertension, and headache, eye pain, nausea and other symptoms may appear. 3. Cerebral hemorrhage: It is an intracerebral hemorrhage caused by rupture of intracranial blood vessels, often combined with hypertension, vascular aneurysm and other underlying diseases, which occurs more suddenly, and may cause dizziness and headache, nausea and vomiting, loss of consciousness and other symptoms. 4. Cerebral infarction: softening and necrosis of brain tissue caused by obstruction of blood vessels in the brain or insufficient blood supply. At the early stage of attack, symptoms such as weakness of limbs, headache and nausea may appear, followed by coma and consciousness disorder. 5. Migraine: It is a kind of common headache, which may be related to mental stress and other physiological factors, with symptoms such as headache, nausea and fatigue. If the headache and nausea are not relieved after resting, you should consult a doctor in time to receive relevant examination and treatment.