Bigfork Animal Hospital

7575 MT HWY 35
Bigfork, MT 59911



What they are:

  •  EOs are aromatic, volatile oils contained within many plants. They can be produced in any part of the plant including the leaves, fruit, rinds, roots, and wood, and many plants produce different oils in various parts of the plant.



  • EOs have been used for approximately 6,000 years. There are records in 4500 BC documenting both physical and spiritual purposes of essential oils. EOs were used by doctors on the battlefields of WWII for both antimicrobial and antipsychotic properties. This use was published in 1937. The first medical clinical reference book was published in 1990 by a French physician and biochemist.


How they work:

  • Once inhaled, the odor molecules travel up the nose, bind to the receptors in the olfactory epithelium, signal the olfactory bulb, which then sends signals to the gustatory cortex and limbic system. This takes only 4 seconds! Sense of smell is the only sense linked directly to the limbic system, all other senses go through the thalamus and are consciously processed in the cerebral cortex.
  • Physiological effects include altered heart rate, respiratory rate, and blood pressure and hormone release. Psychological effects can include triggering memories and emotions.
  • Because oils are lipids they are readily absorbed through the skin into the bloodstream and through cell membranes. 
  • They can be detected in the bloodstream 5 minutes after topical application.



  • Potential usefulness in Veterinary medicine include: behavior issues, anxiety, preventative dentistry, dermatological issues, bacterial cystitis, insect repellant, feline herpes virus, cancer, and wound care.


Quality Control: There are 5 key components one should look for when selecting an essential oil. It may be necessary to contact the company to find out what their quality control standards are and be sure they have a process for adverse events reporting.

  • Identification - EO's need to be identified by the genus and species, and if there is a chemotype (a species where the chemical composition varies by the geographic area where it is grown) that should also be identified.
  • Growth and Harvest - EO's need to be grown under optimal environmental conditions and harvested at peak time, every bottle should have a lot number.
  • Clean production methods - Temperature, pressure, and facility cleanliness are all important in producing a quality oil. This information should be readily available on any credible manufacturing company.
  • Purity - Oils should be "pure, natural, complete, genuine and authentic" meaning that there are no other essential or vegetable oils, solvents, chemicals or synthetic materials added, and the products have not been distilled more than once (redistilled.)
  • Authenticity - Gas Chromatography-Mass spectrometry can be used to analyze oils, both manufacturers and distributors should have testing in place.


Safety: When essential oils are used in a sensible and appropriate manner they are safe, and their use should be free of complications. The FDA lists 66 individual essential oils as Generally Regarded As Safe (GRAS). There are few cases of reported toxic effects; howeer, most of them are due to extremely high doses and/or adulterated products.


Watch out for these possible reactions:

  • Skin reactions - Most are mild and short lived; Oregano, Thyme, and Savory are best to diffuse, dilute or use hydrosols. Avoid topical use of Cinnamon and Citrus oils unless they are diluted to 10%.
  • Photosensitization - Oils can cause photosensitization causing erythema, rashes, and blisters that can show up 36-72 hours after sun exposure. Avoid direct sunlight (OR LASER THERAPY) for 12-18 hours after use. 
    • Avoid topical use of Bergamot, Grapefruit, Lemon, and Orange. Look for steam distilled instead of cold pressed for these and the photosensitizing compound will no longer be in the EO.
  • Toxic Ketones and Liver Damage/Neurologic Effects - Some oils have toxic forms that can cross the blood brain barrier causing seizures and have been reported to cause liver damage.
    • Avoid these oils with high toxic ketones: Artemesia herba alba (Mugwort Oil), Artemesia absinthum (Wormwood oil), Hyssopus officinalis (Hyssop oil), Lavandula stoechas (Crested Lavender Oil), Mentha pulegium (Pennyroyal oil), Ruta graveolens (Rue oil), Santolina chmaecyparisius (Santolina oil), Thuja occidentalis (Thuja oil)
  • Kidney Toxicity - Juniper, Sandalwood, and Turpentine have been reported to cause renal damage.
  • Coagulation Disturbance - Wintergreen causes an inhibition of platelet aggregation.
  • Changing Blood Glucose -  Avoid using Cinnamon, Geranium, and Lemongrass with Diabetes.