Diseases that cause hyperviscosity of the blood can result in otologic symptoms--especially vertigo. These symptoms are predominantly produced by peripheral vestibular involvement. The pathophysiology probably involves vascular obstruction in the venules. Specific changes in the microvasculature are presumed to be comparable to those that occur with hyperviscosity disorders in the retina. Maintenance of a normal blood viscosity will prevent damage to the ear, as well as other organs. Additionally, reduction of the blood viscosity can greatly improve otologic symptoms. Case studies and a review of the pertinent literature are included.