What is an essential oil?

Essential oil is derived from aromatic plants, herbs, flowers or trees using a process of water, steam or dry distillation. An essential oil or essence is a highly concentrated substance: it takes a large quantity of raw plant material to produce a single drop.

Like all commercially available items essential oils vary dramatically in quality and content. Cheaper oils may be adulterated or extended by the addition of synthetic substances or other oils. Some oils are organically produced and some are not; some are quality controlled by laboratory testing and some are never checked. Always purchase essential oils from a reputable source. Lavender is a particular problem as many essential oils called simply Lavender are not extracted from Lavender (Lavandula angustifolia) at all.

Unlike ordinary vegetable oils, such as olive oil, essential oils are non-oily and highly volatile: they will evaporate if left in the open air. The chemistry of essential oils is complex. Most consist of hundreds of components including terpenes, alcohols, aldehydes and esters. The relative quantities of constituent chemicals will vary between extraction processes. Using an essential oil of the same botanical origin from two different sources does not guarantee the same results.

As complex substances, they can have complex effects on the human body. Lavender, for instance, is thought to provide antiseptic, antibacterial, antibiotic, antidepressant, analgesic, decongestant and sedative effects. Moreover, due to their molecular structure, and lipophylic nature they can be absorbed directly into the bloodstream through the skin. Once inside the body some of these compounds mimic the effect of our hormones, so special care should be taken using essential oils whilst pregnant, even in the very early stages of pregnancy.

Essential oils also reach the bloodstream as a result of the aromatic molecules being inhaled. In the lungs, they pass through the tiny air sacs to the surrounding blood capillaries by the process of diffusion. Once in the bloodstream the aromatic molecules interact with the body's chemistry. This effect is known as aromatherapy. Care should be employed with any therapeutic agent as anything that can affect the body may cause harm if used inappropriately or without due understanding of the effects it may have. This article is intended to provide a brief overview of the health and basic safety concerns for anybody working regularly with essential oils.