Thieves essential oil is supposed to help keep you from getting sick by killing germs.

Packed with powerful, germ-killing essential oils, the Thieves line helps eliminate airborne bacteria and boost the immune system. The Thieves Kit offers protection during cold and flu season of winter months.

However, I am wondering what scientific evidence is available that supports this. I am looking for clinical studies, etc. that support the claims made by companies that promote this essential oil. Do any exist?

  • 5
    I note "cold and flu" are not airborne bacteria. Also, the meaningfulness of "boost the immune system" has been debated here before.
    – Oddthinking
    May 13, 2012 at 4:18
  • 1
    Note the disclaimer at the bottom of the page: These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
    – Henry
    May 13, 2012 at 10:21
  • 1
    I notice nobody pointed this out, sorry for the late comment: it doesn't claim to protect AGAINST cold and flu, just that it "offers protection" during winter, when colds and flus are more common. Presumably it only protects against bacteria, but it happens to do so just as well in winter as summer. Sep 24, 2012 at 15:41
  • sciencedirect.com/science/article/pii/S1010518209000523 I found this article that seemed legit.
    – user20800
    Jun 18, 2014 at 14:21
  • You can look this up yourself at pubmed.gov by doing a search on any or all of the individual oils listed in Thieves. Here are examples of a few: ncbi.nlm.nih.gov/pubmed/18095427 ncbi.nlm.nih.gov/pubmed/17562569
    – user21450
    Jul 31, 2014 at 17:57

1 Answer 1


Plants have evolved various defence mechanisms including antiseptic, antibiotic and antifungal components. Some of these are collected in so-called "essential oils" and these oils can certainly have an impact. Perhaps the best known is tea tree oil. Some essential oils are toxic in high concentrations and some others seem merely to smell nice.

As for Thieves essential oil, which seems to be a mixture of Clove, Lemon, Cinnamon Bark, Eucalyptus and Rosemary, the commercial website points a single published study of this particular mixture, in 1998 in the Journal of Essential Oil Research which does show some impact but does not seem to imply it is a cure-all. There is rather more in other publications on the individual components.

As I said in a comment, the Thieves website has a disclaimer

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease

which I think suggests that you should not rely too heavily on it preventing all forms of disease.

  • I think it would be good to quote a little from the study: it only looked at (3 types of) bacteria, not viruses. It only looked at aerosol forms (of the oil and the bacteria). The abstract doesn't mention dosages that may or may not have had real world application.
    – Oddthinking
    May 15, 2012 at 14:29
  • 3
    Also, the study is credited to, among others, Dr. Gary Young, the owner of Young Living - a company which sells Thieves Oil.
    – TehShrike
    Oct 28, 2013 at 18:52
  • 2
    @TehShrike: It's "D. Gary Young". D is for Donald. He was certainly not a doctor of any kind :) Mar 20, 2020 at 17:49

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