Much of the cutting-edge research on essential oils is done in Europe, particularly France, so we don't have much available in English.  There is still a good deal of research interest in essential oils in the United States, often dealing with the antimicrobial effects of the oils.  "In France today," wrote Julia Lawless, an expert in aromatherapy, "many medical doctors and hospital prescribe essential oils as an alternative to antibiotic treatment, whereas in most other countries the idea of using natural aromatics as form of medical treatment is still very radical" 

In France, many trained medical doctors use essential oils and herbs to fight common infections. They are primarily used for respiratory infections, but they are also useful against infections of the digestive system, the urinary tract, the reproductive organs, and the skin.  French doctors do not limit themselves to practicing only herbal medicine, but incorporate the full extent of modern medical knowledge and skill into their approach to medical care.

The French are world leaders in the field of aromatherapy, the use of essential oils for therapeutic purposes.  Since medical aromatherapy treatments are considered normal and routine, treatments using herbs and essential oils are covered by health insurance plans.  People in France can go to pharmacies where formulas consisting of essential oils and herbal tinctures are specifically made under a doctor's prescription.  Medical aromatherapy is taught in colleges, universities, and medical schools. 

Q: Is there any research documenting the properties of therapeutic oils?

Much of the cutting-edge research on essential oils is done in Europe, particularly France, so we have little available in English.  An excellent book "What To Do When Antibiotics Don't Work!" How to stay healthy and alive when infections strike. by Dirk Van Giles.

A. Oils, such as peppermint, have been reviewed for their ability to block pain, reduce headache, and block indigestion (Dvorshak et al., 1995). Melaleuca oil has been used to treat acne (Bassett et al., 1990). And lavender oil has been examined for its role in inducing relaxation, (Hirsch, 1991), counteracting travel sickness (Bradshaw et al., 1998), reducing blood cholesterol, and protecting blood vessels (Siurin et al., 1997; Nikolaevskii et al, 1990).

Coriander and dill oil have been studied for their effects on diabetes in animal studies (Farag et al., 1984). In an article entitled, "Anticarcinogenic Effects of the Essential Oils from Cumin, Poppy and Basil", some essential oils were also researched for their effect on tumor growth (Aruna et al., 1996).

Q: Is it true that essential oils can kill different kinds of fungi, bacteria, and viruses?

A. Extensive studies have discussed the antibacterial, anti fungal, and antimicrobial properties of many essential oils. Research published by the university of Georgia, Weber State University, the Journal of the American Pharmaceutical Association, and numerous other journals have documented the ability of essential oils to kill many strains of fungi, viruses, and gram negative and positive bacteria. Some of these include Staphylicoccus pneumoniae (responsible for lung and throat infections), Herpes simplex, Salmonella, typhosas, and Pseudomonas aeroginosa.

An interesting study compared a standard medical treatment of acne, benzolperoxide, a topical antibiotic, with tea tree essential oil. Both treatments worked equally well, although the chemical treatment had more side-effects of skin scaling and pruritis, dryness, redness, stinging and burning than the tea tree oil.  The essential oil took more time to work, but the lack of adverse side-effects was thought to make up for its slow onset ("A comparative study of tea-tree oil versus benzolperoxide in the treatment of acne," Medical Journal of Australia, Vol. 153, 15 Oct. 19980, 455-458

In a Russian study on humans, doctors tried essential oils of peppermint, lemon, sage and lavender on patients with chronic bronchitis, residing in a health resort.  They found that inhaling the oils speeded up conventional treatments offered in the resort, as well as demonstrating anti-inflammatory responses (Shubina LP, Siurin SA, Savchenko VM, "Inhalations of essential oisl inthe combined treatment of patients with chronic bronchitis, Vrath Delo 1990 May;(5):66-7)

Research in the 1970's had demonstrated that the essential oils of thyme, oregano, turmeric, savory, romemary and sage, all containing thymol, were effective against Cl. botulinum (source of botulism) and staphylococcus aureus (staph infections), as well as other organisms.  This is particularly important because in hospitals, certain strains of staph have become so virulent, from overuse of antibiotics, that there is only one antibiotic left that will kill them. When the staph germs become resistant to that, they say, there will be nothing that can work.  However, essential oils do not create such a resistance; they remain effective.  In other words, bacteria and viruses do not adapt or create resistance to essential oils; they simply die, and the body's immune system is enhanced rather than depleted.  Thymol, as contained in the oils we just mentioned and others as well, also inhibits the growth of and toxin production of various molds.

Jasper C. Maruzzella and Nicholas A. Sicurella (Journal of the American Pharmaceutical Association, Vol, 49, No. 11, pp. 692-694) investigated 133 essential oils to see if they killed bacteria.  They point out that as early as 1887, essential oils were proven to be effective against anthrax!  Over the years, various researchers have looked into the anti-bacterial action of essential oils.  Maruzzella and Sicurella tested the oils against Staph aurens, B. subtilius, S fecalis, and E.coli. They pointed out that the Gram-postivie bacteria was more susceptible to essential oils than Gram-negative bacteria.  They provided an extensive chart demonstrating the effectiveness of the various oils.

Here is research reference documenting the therapeutic properties of essential oils.

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