Abstract
Transient hearing improvement was recorded in around 60% of patients with Menière's disease 2 hours after the ingestion of 20 g of urea perorally. Urea slightly increased the serum osmolality, which is thought to cause a transient reduction of the endolymphatic hydrops. Urea has no inconvenient side effects and is recommended primarily as a test substance for the verification of endolymphatic hydrops, in conformity with glycerol.