Tea Tree Oil: An Evaluation

When you look around the web for green cleaning or eco-friendly cleaning products, especially the home-made kinds, you will sometimes come across Tea Tree Oil. This is not to be confused with the tea you drink. Tea Tree Oil comes from a different plant altogether. Tea Tree Oil comes from a tree in Australia known as melaleuca alternifolia.

Warning: Tea Tree Oil, which can be purchased in health food stores or online, is toxic and should never be swallowed. Even though you can buy it as a mouthwash (e.g. DESERT ESSENCE, Tea Tree Oil Mouthwash Spearmint - 8 fl oz) you should not even swallow the mouthwash version. And it probably should not be put in the ears because it may cause hearing loss. [See these warnings by the Mayo Clinic]

The great thing about tea tree oil is that it has antimicrobial properties. People claim that it can be used to treat a variety of medical conditions including acne (DDF Benzoyl Peroxide Gel 5% with Tea Tree Oil 2 oz (59 ml)), dandruff (Neutral ph Tea Tree Oil Shampoo 16 fl oz (474 ml) Liquid), warts, athletes foot (FungaSoap Pedifix Liquid with Tea Tree oil - 6 oz.), and many more. But you have to be careful, even when you apply it topically to your skin, because some people have adverse reactions to it, especially if you use the undiluted oil.

The Mayo Clinic's conclusion is that for every human trial that's been conducted "there is a lack of definitive available evidence for the use of tea tree oil in any of these conditions, and further study is warranted."

However, what I'm interested in is should it be used as a disinfectant or to kill mold and mildew? Should I add it to my cleaning solutions? I'm not really sure that there is sufficient scientific evidence to warrant it's use in cleaning products either. Here's my reasoning:

1. First, there is reasonable evidence that tea tree oil does have antimicrobial properties. This fact is not in dispute.

2. However, at the low levels that it is used in cleaning solutions, it can create microbial resistance.

3. In the long run, creating resistent strains of dangerous microbes is more detrimental to humans.

Therefore, for now I'm not going to use tea tree oil in my household cleaning products.

The study where I got this information can be found here: http://jac.oxfordjournals.org/cgi/content/full/59/1/125