Enflurane (2-chloro-1, 1,2-trifluoroethyl-difluoromethyl ether: Ethrane, Ohio Medical Products) has rapidly become very popular, and is the inhalation agent most frequently used at this hospital. Enflurane is biotransformed in part to inorganic fluorid ion.1Fluoride ion-induced nephrotoxicity has been established as a cause of the vasopressin-resistant polyuric renal failure occasionally seen following exposure ot significant doses of methoxyflurane.2Postanesthetic renal failure in a patient who received enflurane led to measurement of serum fluoride in a search for a possible etiologic factor.