Central pontine and extrapontine myelinolysis are well-recognized osmotic demyelination syndromes related to the rapid correction of hyponatremia, chronic alcoholism, and malnutrition. They are reported to show brain stem signs and various movement disorders. A 58-year-old man with a history of chronic alcoholism was admitted for dysarthria, dysphagia, and gait disturbance that had developed five days after a right forearm cellulitis. Magnetic resonance imaging revealed demyelinating patterns in the central portion of the pons and both thalami. He showed severe extrapyramidal symptoms with truncal swaying and postural instability that resulted in severe gait disturbance. Postural instability showed little improvement after conventional physical therapy, but his symptoms markedly improved after five days of dopamine administration. Cessation of dopamine agents was attempted two times, but postural instability and gait disturbance recurred. Therefore, medication was continued for one year. The patient showed stable gait and no further deterioration of postural instability during dopamine therapy.