An evaluation of the mutagenic potential of commercially available tea tree oil in the United Kingdom

Commercially available tea tree oils were tested. Despite a previous report demonstrating a possible mutagenic trend in a single commercially available tea tree product, no mutagenic effect was determined in any of the brands of tea tree oil on any of the strains of Salmonella examined with or without metabolic activation. The same negative results were obtained for the terpinen-4-ol component examined. There was a clear evidence of toxicity of tea tree oil on all Salmonella strains and also by terpinen-4-ol at higher dose levels. It is suggested that terpinen-4-ol may contribute significantly to the widely reported antibacterial activity of tea tree oil.