Insufficient blood supply to the brain results in dizziness, nausea, and vomiting. Insufficient blood supply refers to insufficient blood supply to the posterior circulation, which is the inadequate blood supply to the vertebrobasilar artery. The blood vessels in the brain are a Willis ring, divided into an anterior circulation and a posterior circulation. The posterior circulation mainly supplies the cerebellum and the brainstem, as well as part of the occipital lobe. The cerebellum and brainstem are the ones in charge of balance, and when they are ischemic or infarcted, dizziness, visual rotation, nausea, vomiting, and problems with vision and visual field will occur. Therefore, dizziness and vomiting will occur with inadequate blood supply to the brain, but the single reference is to the inadequate circulation of blood supplied by the vertebrobasilar artery in the posterior circulation. The anterior cerebral circulation, including the middle and anterior cerebral, ischemia are dominated by numbness and weakness of the limbs, functional deficits, and speech and naming aphasia. Therefore, inadequate blood supply to the vertebrobasilar artery in the posterior circulation results in dizziness, nausea, vomiting, and in severe cases, panic and sweating.