What Are Essential Oils?

Essential oils are, "Highly aromatic substances made in plants by special cells but at this stage the material is not yet an essential oil, but is called an essence. It becomes an essential oil only after it has been extracted by distillation."
Essential oils embody the plants from which they are extracted from in a number of ways: chemically, physically, aromatically, and spiritually.

- National Association For Holistic Aromatherapy


Essential oils are a complex make-up of volatile chemical components. These include, but are not limited to, phenols, alcohols, aldehydes, and esters. Each chemical component contributes to the overall therapeutic effect of the essential oil. An essential oil's chemical make-up may vary from the plant from which it was extracted from due to its method of extraction; for example, distillation vs. carbon dioxide extraction vs. expression.


Factors such as environment, altitude at which the plant was grown at, geographical location, time and method of harvesting of the plant can alter the chemical components of the final essential oil.


The aroma of an essential oil may not resemble the aroma of the plant as closely as you think because of the influences mentioned above. However, a true essential oil should be subtle in aroma (unlike its synthetic counterpart) and remind you in some part of the plant from which it was extracted from. Descriptors for aromas of essential oils are vast but include minty, citrus, floral, balsamic, green, earthy, and woody.


Ancient people, and through to medieval times, believed in the spiritual power of plants, rather than just the chemical breakdown of its healing components. Each plant had a spiritual healing element. For example, the plant rosemary (rosmarinus officinalis) was used in medieval times to drive out evil spirits. A sprig of rosemary, and other such plants, were often hung or planted near the door of the home to protect its inhabitants.