What happened to headache, dizziness, nausea and stomach upset? There are several reasons for the above symptoms: the first one is hypertensive encephalopathy, which refers to the sudden increase of blood pressure in hypertensive patients due to various reasons, with the maximum systolic pressure reaching 210mmHg and diastolic pressure above 110mmHg. Due to intracranial brain cell edema, it will lead to headache, dizziness, and even also accompanied by nausea and vomiting, which is the first cause. The second one is encephalitis. Patients with encephalitis can have fever, especially viral encephalitis, as well as headache, dizziness, nausea and vomiting. Third, cerebral hemorrhage, cerebral hemorrhage is a kind of cerebral stroke, which is usually seen in patients with hypertension and arteriovenous malformation, etc., and the above phenomena can occur after the attack. Fourthly, infections caused by various reasons can lead to headache, dizziness, nausea and stomach discomfort when fever occurs.