There are many aspects that cause sudden dizziness, nausea and unsteadiness in standing. In this case, there may be the following aspects: first, diseases with a higher potential risk, mainly cerebrovascular diseases, such as infarction or hemorrhage in the cerebellum and brain stem area, patients will have dizziness, nausea, unsteadiness in standing and even other symptoms of neurological deficits. Secondly, if the patient has dizziness, nausea and unsteadiness related to the change of head position, which is transient in nature and lasts for less than one minute, this condition should be considered as benign paroxysmal positional vertigo. Thirdly, patients with sudden dizziness, nausea and unsteadiness may also be caused by cervical spine disease, or by insufficient blood supply to the brain or ischemia in the posterior circulation.