Sudden dizziness and nausea may be caused by physiological factors, Meniere’s disease, hypertension, cervical spondylosis and other reasons. 1. Physiological factors: Changes in body position, prolonged late-night sleep, excessive fatigue and other reasons may lead to insufficient cerebral blood supply and sudden dizziness and nausea. 2. Ménière’s disease: Ménière’s disease is an idiopathic inner ear disease caused by the occurrence of fluid in the membranous labyrinth, which manifests itself in recurrent and sudden episodes. Patients may have nausea, vomiting, tinnitus and other symptoms. 3. Hypertension: When blood pressure is significantly elevated, it will lead to increased pressure on the blood vessels in the brain, causing discomfort in the head, so dizziness and nausea occur. 4. Cervical spondylosis: Cervical spondylosis, caused by poor living habits or working posture, may lead to insufficient blood supply to the vertebral artery, so sudden dizziness and nausea occur. Dizziness and nausea may also be caused by other factors, when the patient has sudden dizziness and nausea, after excluding physiological factors, should go to the hospital in a timely manner, please ask the doctor for a clear diagnosis and treatment.