A Review of the Toxicity of Melaleuca Alternifolia (Tea Tree) Oil

Food Chem Toxicol. 2006 May;44(5):616-25. doi: 10.1016/j.fct.2005.09.001. Epub 2005 Oct 21.

Abstract

The essential oil of Melaleuca alternifolia, also known as tea tree or melaleuca oil, is widely available and has been investigated as an alternative antimicrobial, anti-inflammatory and anti-cancer agent. While these properties are increasingly well characterised, relatively limited data are available on the safety and toxicity of the oil. Anecdotal evidence from almost 80 years of use suggests that the topical use of the oil is relatively safe, and that adverse events are minor, self-limiting and occasional. Published data indicate that TTO is toxic if ingested in higher doses and can also cause skin irritation at higher concentrations. Allergic reactions to TTO occur in predisposed individuals and may be due to the various oxidation products that are formed by exposure of the oil to light and/or air. Adverse reactions may be minimised by avoiding ingestion, applying only diluted oil topically and using oil that has been stored correctly. Data from individual components suggest that TTO has the potential to be developmentally toxic if ingested at higher doses, however, TTO and its components are not genotoxic. The limited ecotoxicity data available indicate that TTO is toxic to some insect species but more studies are required.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Administration, Oral
  • Administration, Topical
  • Animals
  • Anti-Infective Agents, Local / adverse effects
  • Anti-Infective Agents, Local / therapeutic use
  • Anti-Infective Agents, Local / toxicity
  • Anti-Inflammatory Agents / adverse effects
  • Anti-Inflammatory Agents / therapeutic use
  • Anti-Inflammatory Agents / toxicity
  • Antineoplastic Agents / adverse effects
  • Antineoplastic Agents / therapeutic use
  • Antineoplastic Agents / toxicity
  • Biological Assay
  • Cell Line
  • Dermatitis, Allergic Contact / etiology*
  • Dermatitis, Allergic Contact / immunology
  • Humans
  • Tea Tree Oil / adverse effects*
  • Tea Tree Oil / chemistry
  • Tea Tree Oil / therapeutic use
  • Tea Tree Oil / toxicity*

Substances

  • Anti-Infective Agents, Local
  • Anti-Inflammatory Agents
  • Antineoplastic Agents
  • Tea Tree Oil