thieves-doesitwork-juicygreenmomEven if you’re not familiar with the world of essential oils, you may have heard of the famous Thieves blend being used for supporting a healthy immune system. It was actually the reason I first decided to give essential oils a try (because I honestly thought it was hokey, and frankly did not like scents). So – does Thieves essential oil really work? Sound scientific research is very important to me, so I’m going to share what I’ve found.

The Young Living Thieves blend of essential oils (this is why I primarily use Young Living oils) is made up of Clove, Lemon, Cinnamon Bark, Eucalyptus Radiata, and Rosemary. The legend is that 15th century thieves rubbed these oils on themselves during the plague so as not to contract disease while robbing the dead and dying.

I worked as a researcher in the first 6 years of my Speech-Language Pathologist career in the area of head and neck cancer. This experience has provided me with expertise in interpreting scientific research. I say this because I believe my credentials say something about my ability as a scientist; I’ve seen many “crunchy moms” be dismissed and scoffed at by the scientific community. Well, it’s possible to be a crunchy mom and a scientist. For reals. (If you really want to know, here’s my list of scientific publications in peer-reviewed academic journals.) Ok, enough bragging. Here are some of the studies I looked at:

The one study most people cite includes Gary Young as an author (the founder and CEO of Young Living). It tested the diffusion of Thieves against 3 strains of airborne bacteria, and found that it reduced 44%, 82% and 96% of each one after 10 minutes of diffusing. Now I get that people are all riled up because the Young Living guy is an author on this study, so I decided to look for other evidence. (However I also believe that this study shouldn’t be completely disregarded. Just because he is an author doesn’t mean he made it all up.)

Deans & Ritchie (1987) looked at 50 different essential oils and their antibacterial properties against 25 types of bacteria. The 10 most inhibitory and comprehensively inhibitory oils included Cinnamon and Clove.

Fu et al (2007) looked at the antimicrobial activity of Clove and Rosemary alone and in combination. Both on their own had significant effects against 3 Gram-positive bacteria, 3 Gram-negative bacteria, and 2 fungi, and the combination of the two oils together had additive, synergistic, or antagonistic effects against each microorganism.

Kalemba & Kunicka (2003) did a review paper of hundreds of studies documenting essential oils and their antimicrobial properties. They stated that Thyme, Oregano, Mint, Cinnamon, Clove, and Salvia had the strongest antimicrobial properties.

Mayaud et al (2008) looked at 13 essential oils and their effect on 65 bacterial strains with varying sensitivity to antibiotics. Their conclusion was that Cinnamon Bark had the highest antimicrobial activity, especially against resistant strains.

Warnke et al (2009) looked at the effect of several essential oils (Eucalyptus, Tea Tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea, and Sage) on antibiotic-resistant strains of bacteria (people get infected often through hospital stays). (I can say for a fact that MRSA which was tested in this study, has been running rampant in our local hospitals for several years.) They found that the strongest oils for inhibiting the bacteria were Thyme white, Lemon, Lemongrass, and Cinnamon. They also found that the other oils also demonstrated considerable efficacy and state that “essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species“. (This article comes from a sound peer-reviewed journal I’m familiar with, the Journal of Cranio-Maxillofacial Surgery.) Warnke did another study showing the same results with a focus on Lemongrass, Eucalyptus and Tea Tree oils (2013).

Goni et al (2009) found that vapour generated by a combination of cinnamon and clove essential oils prevented the growth of 4 types of Gram-negative and 4 types of Gram-positive bacteria.

I have seen some writings from people who say that the “Thieves thing” is a total scam. And that this evidence is useless because it wasn’t done in “real world” situations. So I was very excited to see this home experiment done by someone with a PhD in biochemistry – who also does not use essential oils on a regular basis; so she really wanted to look at this for the science of it. Guess what? Thieves essential oil (undiluted) killed bacteria – better than vinegar, and just as well as hydrogen peroxide. She has also done experiments with diffusing Thieves essential oil and found that it does inhibit bacterial growth.

Other essential oils companies do have some of their own versions of “Thieves” blends as well. And there are lots of DIY Thieves recipes out there on Pinterest.

What do you think about using essential oils for killing germs?


Young Living’s Thieves blend is registered in Canada as a Natural Health Product, shown to help relieve colds and coughs.


  • Deans SG, Ritchie G. Antibacterial properties of plant essential oils. International Journal of Food Microbiology 1987; 5(2): 165–180.
  • Fu Y, Zu Y, Chen L, Shi X, Wang Z, Sun S, Efferth T. Antimicrobial activity of clove and rosemary essential oils alone and in combination. Phytother Res 2007; 21(10): 989-94.
  • Goni P, Lopez P, Sanchez C, Gomez-Lus R, Becerril R, Nerin C. Antimicrobial activity in the vapour phase of a combination of cinnamon and clove essential oils. Food Chemistry 2009; 116(4): 982–989.
  • Kalemba D, Kunicka A. Antibacterial and antifungal properties of essential oils. Curr Med Chem 2003;10(10): 813-29.
  • Mayaud L, Carricajo A, Zhiri A, Aubert G. Comparison of bacteriostatic and bactericidal activity of 13 essential oils against strains with varying sensitivity to antibiotics. Letters in Applied Microbiology 2008; 47(3): 167–173.
  • Warnke PH, Becker ST, Podschun R, Sivanathan S, Springer IN, Russo PAJ, Wiltfang J, Fickenscher H, Sherry E (2009). The The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections. Journal of Cranio-Maxillofacial Surgery 2009; 37(7): 392-397.
  • Warnke PH, Lott AJS, Sherry E, Wiltfang J, Podschun R. The ongoing battle against multi-resistant strains: In-vitro inhibition of hospital-acquired MRSA, VRE, Pseudomonas, ESBL E. coli and Klebsiella species in the presence of plant-derived antiseptic oils. Journal of Cranio-Maxillofacial Surgery 2013; 41(4): 321–326.