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A study of tea tree oil ototoxicity
1Auditory Laboratory, Department of Physiology, University of Western Australia, Nedlands, Australia.
Audiology & Neuro-Otology
|March 18, 2000
Summary
Tea tree oil may treat ear infections, but high concentrations can harm hearing. A diluted form (2%) showed no lasting damage in guinea pigs, suggesting potential safety for short-term use.
Area of Science:
- Ototoxicology
- Microbiology
- Pharmacology
Background:
- Tea tree oil is a potential treatment for otitis externa and media.
- Its ototoxicity has not been previously evaluated.
- Assessing tea tree oil's safety is crucial for its therapeutic application.
Purpose of the Study:
- To investigate the ototoxicity of tea tree oil in guinea pigs.
- To determine safe concentrations and exposure times for potential ear treatments.
Main Methods:
- Compound auditory nerve action potential (CAP) thresholds were measured before and after middle ear oil instillation.
- Guinea pigs were exposed to 100% and 2% tea tree oil concentrations.
- Auditory function was assessed at a high frequency (20 kHz).
Main Results:
- 100% tea tree oil caused temporary threshold elevation at 20 kHz after 30 minutes.
- A 2% tea tree oil solution (in saline with Tween-80) did not result in significant lasting threshold changes.
- The 2% concentration exceeds the minimum inhibitory concentration for many relevant microbes.
Conclusions:
- High concentrations of tea tree oil are ototoxic to the high-frequency cochlea.
- A 2% tea tree oil concentration may be safe and effective for short-term (30 min) ear treatments.
- Further research is required to confirm the safety of tea tree oil for ear infections.