For the sudden onset of dizziness, accompanied by nausea, unsteadiness, first of all must be ruled out potential diseases, potentially dangerous diseases are mainly the following: 1, cerebrovascular disease, acute cerebral infarction or acute cerebral hemorrhage of the cerebellum and brainstem, then the patient must do head CT and magnetic resonance examination. 2, acute myocardial infarction, the patient may be due to acute myocardial infarction, so that the heart in a short period of time to reduce the blood ejection, but the patient’s anterior heart pain symptoms are not obvious. 2, acute myocardial infarction, patients may be due to acute myocardial infarction, the heart in a short period of time to reduce the amount of blood ejection, dizziness, nausea, and unsteady symptoms, but the patient’s anterior region of the heart pain symptoms are not obvious. 3, the internal carotid artery or vertebral artery entrapment, can be due to the sudden emergence of vertebral artery entrapment, resulting in a reduction in the supply of cerebral blood, leading to dizziness, nausea, and the phenomenon of unsteadiness. 4, gas or organophosphorus poisoning, will cause dizziness, nausea and unsteady phenomenon. After excluding the above dangerous diseases, then consider whether the patient is due to insufficient cerebral blood supply caused by dizziness, nausea, unsteadiness.