An essential oil is the aromatic (it has an aroma) volatile (evaporates rapidly) liquid distilled from a plant. Just as not all plants have an aroma, not all plants have essential oils. The chemistry of an essential oil is very complex, many of them having hundreds or even thousands of different and unique chemical compounds. When a plant is dried to make an herb, much of the therapeutic value is lost as the essential oils evaporate off.
The chemical constituents of an essential oil are critical to determine its purity. These constituents can be affected by a number of variables. These include:
- The part of the plant used to obtain the oil
- Soil conditions, presence of chemical fertilizers
- The region of the world and climate the plants were grown in
- Harvesting methods and timing
- The processes used to obtain the oil
Adulterated oil is oil that has been processes, altered, mixed with other, cheaper substances in order to appear to be pure oil. These oils do not have the health affects of certified pure therapeutic grade oils. When people use adulterated oils and they adverse reactions, such as a skin burn or rash, they conclude that ALL essential oils are bad. This is not the case.