Ototoxicity of baby oil in a chinchilla animal model

Objective: Baby oil is commonly used to soften ear wax in order to aid its removal. The aim of this study was to determine the potential ototoxicity of baby oil.

Method: A prospective controlled animal study was conducted using ten chinchillas with normal hearing function. Each had bilateral myringotomies. One ear was randomly assigned to receive 1 ml of baby oil while the other ear received an equal volume of 0.45% NaCl. Distortion product otoacoustic emissions (DPOAEs) and Auditory Brainstem Response (ABR) measurements were recorded at baseline (post myringotomy and pre application of product) and on days 5 and 15 after application. Two months after application of baby oil, the cochleae were processed for light microscopy and qualitative comparisons were made between the cochleae of both control and experimental ears.

Results: There was no statistically significant difference in DPOAE between experimental and control ears at 5 and 15 days after treatment. ABR results did not reveal ototoxicity at days 5 and 15 post treatment. None of the animals developed facial paralysis or any signs of vestibular toxicity. There were no overt mucosal changes in the middle ear of the ears exposed to baby oil compared to the control ears. Light microscopy showed comparable features in the organ of Corti, stria vascularis, spiral ligament and the spiral ganglion cells of both groups of cochleae.

Conclusion: Baby oil did not produce ototoxic effects when applied ototopically in chinchillas with non-intact tympanic membrane.