Essential oils have been used for thousands of years as evidenced by Egyptian hieroglyphics, the Bible and Chinese manuscripts. The predominant method of action of essential oils results from the inhaling of particular scents which trigger the production of specific neurochemicals in the brain. They are volatile liquids that are distilled from plants and their respective parts. One to the factors that determine the purity and therapeutic value of an oil is its chemical constituents such as climate, altitude, geographical region, season, etc. We suggest seeking out the purest quality and highest therapeutic grade oil available as anything less may not produce the desired results and/or toxicity.