Sudden vertigo and unstable standing need to be analyzed in the context of the patient’s medical history and the onset of the disease. First, if the patient has sudden vertigo, mainly with a change of position, and the vertigo lasts for a relatively short time, usually less than one minute, in this case it is considered to be paroxysmal benign positional vertigo, which is also known as otoliths. Secondly, if the patient’s dizziness is unstable in standing, accompanied by discomfort in the back of the head and neck, then the possibility of cervicogenic dizziness should also be considered. Thirdly, if the dizziness occurs when the patient suddenly stands up from a squatting position or from a sitting position, then in this case, it should be considered as postural hypotension, because after suddenly standing up, the blood pressure drops too fast and the blood supply to the brain is insufficient, and then the symptoms of dizziness and unsteadiness appear, which may also be accompanied by blackness and grayness in front of the eyes.