Headache and nausea may be caused by cerebral hemorrhage, meningitis, hypertension, encephalitis B and other diseases. 1. Cerebral hemorrhage: numbness of limbs, headache and nausea, blurring of consciousness and even fainting will occur in acute onset. 2. Meningitis: it is categorized into viral meningitis, bacterial meningitis and purulent meningitis, which may present with fever and chills, headache and nausea, vomiting and other symptoms. 3. Hypertension: Hypertension occurs when the systolic blood pressure is greater than or equal to 140 mmHg and diastolic blood pressure is greater than or equal to 90 mmHg. When the blood pressure is too high, there will be headache, nausea, eye swelling, dizziness and other clinical manifestations. 4. Encephalitis B: It is an infectious disease caused by encephalitis B virus infection. The initial manifestations are headache, nausea, vomiting, gradually progressing to drowsiness, coma, impaired consciousness. If the headache and nausea are not relieved and accompanied by the above symptoms, you should go to the hospital in time to receive professional treatment.