Tea tree oil: in vitro efficacy in otitis externa

J Laryngol Otol. 2005 Mar;119(3):198-201. doi: 10.1258/0022215053561495.


Objective: The purpose of this study was to determine the susceptibility of organisms causing otitis externa (OE) to the essential oil of Melaleuca alternifolia, or tea tree oil (TTO).

Methods: Fifty-seven swabs were taken from the ears of 52 patients with OE for culture and sensitivity. A broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of TTO for each organism.

Results: In 51 percent of the swabs taken, pathogenic organisms were cultured. Of these cultures 71 percent, both bacteria and yeast, were susceptible to TTO 2 percent or less. The only organism showing resistance to TTO was Pseudomonas aeruginosa; however 25 percent of these bacteria were sensitive.

Conclusion: Tea tree oil may have a role to play in the treatment of OE. However, more work needs to be done to enhance the anti-pseudomonal effect and to assess ototoxicity.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anti-Infective Agents, Local / pharmacology*
  • Child
  • Child, Preschool
  • Dose-Response Relationship, Drug
  • Drug Resistance, Bacterial
  • Female
  • Humans
  • In Vitro Techniques
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Otitis Externa / drug therapy
  • Otitis Externa / microbiology*
  • Phytotherapy*
  • Pseudomonas aeruginosa / drug effects
  • Tea Tree Oil / pharmacology*


  • Anti-Infective Agents, Local
  • Tea Tree Oil