One of the great stories that changed my practice of medicine took place 600 years ago.  Perhaps only a myth, “The Secret of Thieves” speculates that the origin of a well-known anti-infective essential oil blend dates back to the Middle Ages.

“Century after century, bubonic plague outbreaks decimated the population of Asia and Europe for the better part of a thousand years. Out of this period emerged a legend of four thieves who were captured and charged with robbing the dead and dying victims. When the thieves were tried, the magistrate offered leniency if they would reveal how they resisted contracting the infection as they performed their gruesome acts. They told of a special concoction of aromatic herbs, including garlic, cloves and rosemary, that they rubbed on themselves before committing their crimes.”

Supposedly after confessing to King James of England, the thieves were summarily silenced – but their secret lives on today.

Flash forward a few hundred years.  Not exactly the Plague, but H1N1 (aka “Swine ’09”) was causing great anxiety.  Everyone was using conventional alcohol- and/or chemical-based hand sanitizers like water.  The alcohol was causing skin irritation in many children, and there were reports (now on the increase) of serious adverse effects from alcohol ingestion.  Triclosan, a toxicant found in chemical-based products, has been linked to immune dysregulation and endocrine disruption.  I was interested in more natural options and doing research on essential oils when a mom in my practice told me about Young Living Essential Oils’ “Thieves” blend, a patented mixture of cinnamon, clove, lemon, rosemary and eucalyptus oils, similar to the mythical oils used in the Middle Ages.  I wanted to make my own blend, so I contacted my colleague Dr. Kamyar Hedayat, one of the foremost pediatric aromatherapy experts in the country and founder of AromaMD.  In fact, I included a Spotlight section in my new book, “Treatment Alternatives for Children,” on essential oils and aromatherapy, and Dr. Hedayat provided this statement:

“Essential oils are a wonderful healing approach for children. Newborns recognize their mother by scent, not sight. Children explore the world by smelling things. As we age, a single scent can trigger a flood of memories. As you cuddle your child in your arms when sick, allowing them to smell a few drops of lemon and eucalyptus can ease their breathing and reduce their fever. As they fall asleep at night, a gentle foot or hand rub with lavender and marjoram will send them off into the sweet and gentle night with a sweet and soothing scent. Essential oils are more than a sweet smell. They calm the nerves, aid the body, and soothe the soul.”

So Dr. Hedayat hooked me up with medical-grade oils, I added aloe vera gel and water, and voila!  Instant DIY natural hand sanitizer.  We use it daily at the Whole Child Center, and I’ve taught hundreds of kids and their families how to make it.   Here’s a how-to video.  Sometimes we substitute orange or grapefruit oil for the lemon, just to vary the aroma.  It became so popular and families kept asking us to make them more that we partnered with Kristina at Poofy Organics, and now she makes and bottles the blend (“Clean Clappers”) for us.

I’ve been asked from time-to-time (including by the New York Times) for data supporting the anti-microbial efficacy of these oils.  Here is a selection of relevant scientific research.

Mechanisms of Action (from Natural Medicines Comprehensive Database)

Cinnamon 

The applicable parts of cassia cinnamon are the bark and flower. Cinnamaldehyde is found in the volatile oil fraction of cassia cinnamon. Cinnamaldehyde seems to have antibacterial activity.

Clove

The applicable parts of clove are the oils, flowers, leaves, and stems. Clove oil contains up to 95% eugenol.  Clove oil inhibits gram-positive and gram-negative bacteria. It also has fungistatic action, and anthelmintic and larvicidal properties.

Rosemary

The applicable part of rosemary is the leaf. The active constituent of rosemary leaves is the essential oil. The oil consists primarily of cineole, borneol, camphor, and pinenes. Rosemary also seems to have antibacterial, antifungal, and antioxidant properties.

Eucalyptus

The applicable parts of eucalyptus are the leaf and oil. Eucalyptus oil, which is made from the leaves and branches of eucalyptus, contains 60% to 90% eucalyptol (1,8-cineole). Eucalyptus leaf extracts seem to have antimicrobial and antifungal activity.

Published Studies (from PubMed)

Comparison of bacteriostatic and bactericidal activity of 13 essential oils against strains with varying sensitivity to antibiotics. Mayaud L, Carricajo A, Zhiri A, Aubert G. Lett Appl Microbiol. 2008 Sep;47(3):167-73.

The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections. Warnke PH, Becker ST, Podschun R, Sivananthan S, Springer IN, Russo PA, Wiltfang J, Fickenscher H, Sherry E. J Craniomaxillofac Surg. 2009 Oct;37(7):392-7.

Effect of plant oils on Candida albicans. Agarwal V, Lal P, Pruthi V. J Microbiol Immunol Infect. 2010 Oct;43(5):447-51.

Evaluation of bacterial resistance to essential oils and antibiotics after exposure to oregano and cinnamon essential oils. Becerril R, Nerín C, Gómez-Lus R. Foodborne Pathog Dis. 2012 Aug;9(8):699-705.

Antimicrobial activity of commercially available essential oils against Streptococcus mutans. Chaudhari LK, Jawale BA, Sharma S, Sharma H, Kumar CD, Kulkarni PA. J Contemp Dent Pract. 2012 Jan 1;13(1):71-4.

Increasing antibiotic activity against a multidrug-resistant Acinetobacter spp by essential oils of Citrus limon and Cinnamomum zeylanicum. Guerra FQ, Mendes JM, Sousa JP, Morais-Braga MF, Santos BH, Melo Coutinho HD, Lima ED. Nat Prod Res. 2011 Dec 23. [Epub ahead of print]

Antibacterial activity and anticancer activity of Rosmarinus officinalis L. essential oil compared to that of its main components. Wang W, Li N, Luo M, Zu Y, Efferth T. Molecules. 2012 Mar 5;17(3):2704-13.

Chemical composition and antimicrobial activity of Rosmarinus officinalis L. essential oil obtained via supercritical fluid extraction. Santoyo S, Cavero S, Jaime L, Ibañez E, Señoráns FJ, Reglero G. J Food Prot. 2005 Apr;68(4):790-5.

Antimicrobial activities of eucalyptus leaf extracts and flavonoids from Eucalyptus maculata. Takahashi T, Kokubo R, Sakaino M. Lett Appl Microbiol. 2004;39(1):60-4.

Chemical Composition of 8 Eucalyptus species’ Essential Oils and the Evaluation of Their Antibacterial, Antifungal and Antiviral activities. Elaissi A Ae, Rouis Z Zr, Abid NB Na, Mabrouk S Sm, Ben Salem Y Ybs, Bel Haj Salah K Kb, Aouni M Ma, Farhat F Ff, Chemli R Rc, Harzallah-Skhiri F Fhs, Khouja ML Mlk. BMC Complement Altern Med. 2012 Jun 28;12(1):81. [Epub ahead of print]