Pure-tone audiometry and transiently evoked otoacoustic emission (TEOAE) measurements were made before and after glycerol administration in the ears of sensorineural hearing loss with three different clinical entities, i.e. Meniere's disease, cochlear Meniere's disease and unilateral sensorineural hearing loss of unknown cause without hearing fluctuation (SNHLWF). TEOAE was evoked after glycerol administration in several ears of Meniere's disease and cochlear Meniere's disease, in which it was not evoked before glycerol administration. Especially in patients with cochlear Meniere's disease, TEOAE was altered without an accompanying significant change in mean hearing level. The change in TEOAE after glycerol administration indicates that the active motile property of outer hair cells may be affected by endolymphatic hydrops.