The Basics of Essential Oils: The Science Behind Aromatherapy


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Essential oils contain many individual chemical components, istockphoto (royalty free)

Essential oils contain many individual chemical components. Image by ISP

Plant Families and Chemical Components

Plants that belong to the same botanical family often share similar physical characteristics and features; this is true of many aromatic plants with medicinal properties.

Aromatherapists can even substitute the use of one essential oil for an essential oil with similar chemical make-up, if it belongs to the same plant family, because it may have very similar medicinal properties.

Although each essential oil is unique in its chemical make-up, essential oils extracted from common plant species typically share the same chemical components.

There are over 200 aromatic plants which produce an essential oil of some sort, although not all of them are used in the practice of clinical aromatherapy because of high toxicity levels. There are approximately twenty one aromatic plant families which produce essential oils used in aromatherapy.

Chemical Components of Essential Oils

All essential oils are made up of carbon, oxygen, and hydrogen; the chemistry of essential oils is complex but in simple terms, all essential oils hold a combination of mono and sesquiterpenic molecules of the following chemical components:

  • acids
  • alcohols
  • aldehydes
  • coumarins
  • esters
  • furanocoumarins
  • hydrocarbons
  • ketones
  • phenols

Understanding the Chemistry of Essential Oils

Essential oil chemistry is complex, but it is possible to demystify the chemistry of essential oils and the individual chemical components. We can evaluate the effectiveness of essential oils through the study of clinical aromatherapy, combined with chemistry and a little botany – it’s not as difficult as  you think.


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Woelk, H & Schlafke, S. A multi-center, double-blind, randomizsed study of the lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder(2009). Phytomedicine, 17, 94-99. Accessed November 30, 2012.

Takarada, R. et al. A comparison of the antibacterial efficacies of essential oils against oral pathogens. (2004). Oral Microbiology and Immunology, 19, 61-64. Accessed November 30, 2012.

Clarke, S. Essential Chemistry for Aromatherapy. (2008). UK: Churchill Livingstone.

Price, S. Aromatherapy Workbook. (2000). UK:Thorsons.

Price, S., Price, L. Aromatherapy for Health Professionals. (2001). UK: Churchill Livingstone.


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