Aromatherapy for Body, Mind & Spirit

The Chemistry of Essential Oils

The Chemistry of Essential Oils

The Chemistry of Essential OilsEssential oils smell incredible, but they are so much more than their pleasing aromas! If you’re like me, you may have initially become interested in essential oils because of their aromas, as well as their healing, therapeutic qualities. However, additionally, I discovered  an exciting new world as I learned about the chemistry of essential oils.

It seems like I’m a mad scientist at times, mixing my special potions! However, I then realize that there’s a method to the madness, and the nerdy student in me comes out. Consequently, I realize I truly want to understand the science and the chemistry of essential oils.

Especially relevant is that categories of chemical compounds exist, and every essential oil, at its core, contains its own unique identity, based on the chemical mix contained in that particular oil. Therefore, knowing this is also a key to understanding why different groups of essential oils are recommended for specific health challenges. It also gives validity to the therapeutic use of essential oils.

Hence, essential oils are not just oils that smell pretty.  Aromatherapists who use them for healing have thousands of years of practice and solid science backing them when they practice aromatherapy.

So, consider this article an introduction to help you appreciate some of the basic concepts of essential oils. Don’t feel you have to memorize any of it – I promise I won’t test you! Rather, simply have fun while you expand your understanding and knowledge of essential oils!

Chemical Groups

Probably the most useful thing you can do is to take a few minutes to read through these basic categories of chemical groups. Doing so will help you realize that essential oils that contain high amounts of these chemicals are recommended for specific issues. Also, you’ll learn more about the properties of each chemical group (i.e. if they are water soluble or if there are safety concerns).


  • Oils rich in monoterpenes are helpful for respiratory issues; decongestant
  • Circulation and pain relief for muscle pain and stiffness
  • Some oils are anti-inflammatory
  • Mild antibacterial and/or antiviral
  • Effective airborne deodorizer/purifier
  • May cause skin irritation
  • Not water-soluble; avoid use in bathtub
  • Store closed in a cool, dark place
  • Grapefruit, Orange, and Balsam Fir contain high amounts of monoterpenes


  • Oils rich in sesquiterpenes can be anti-inflammatory, antibacterial, antiseptic, analgesic, and antispasmodic.
  • Even a small amount contained in an oil can have a profound therapeutic effect; but, unlike other chemical compounds, one cannot generalize the therapeutic effect as easily as with other chemical families.
  • Generally, no safety concerns
  • Black Pepper, Myrrh, Cedarwood, and Sandalwood contain high amounts of sesquiterpenes
  • Effective antifungal (blend with a soothing oil such as Lavender or Sandalwood)
  • Anti-inflammatory; antispasmodic; antibacterial
  • Nervous system tonic (relieve stress; promote relaxation)
  • Cooling
  • Can be irritating to the skin (contains citral; generally safe for skin when used with a carrier oil and combined with oils that are high in monoterpenols)
  • Cinnamon Bark and Lemongrass contain high amounts of aldehydes


  • Gentle to powerful antispasmodic, depending on the oil
  • Sedative
  • Balancing, soothing, regulating (rebalances the sympathetic nervous system and can be emotionally uplifting)
  • Roman Chamomile contains isobutyl angelate, which is considered to be one of the best antispasmodic components available
  • Anti-inflammatory; effective on skin rashes and irritations
  • Adaptogenic (helps body deal with and adapt to stress)
  •  Jasmine, Roman Chamomile, Lavender and Ylang Ylang are analgesic
  • Cardamom, Roman Chamomile and Bergamot are effective digestive aids
  • Generally, no safety concerns when properly diluted


  • Analgesic
  • Rosemary ct camphor, Spike Lavender and Peppermint contain a significant percentage of ketones and are highly effective mucolytics and also act as expectorants, making them valuable to use with respiratory infections.
  • Peppermint contains menthone, a carminative
  • Spike Lavender and Vetiver help with scar and wound healing
  • Peppermint, Rosemary ct camphor and Spike Lavender all have circulatory effects
  • All ketones do not have the same safety concerns or therapeutic behaviors so each component should be considered individually. 


  • Oils high in oxides can be powerful respiratory aids
  • Essential oils containing significant amounts of 1,8 cineole have antiviral, antifungal, antibacterial and expectorant/mucolytic effects.
  • 1,8 cineole also has a stimulating effect on the mental process, increasing blood flow to the brain when inhaled.
  • Research has shown 1,8 cineole to decrease coughing and shortness of breath, as well as ease expectoration. It also has an anti-inflammatory effect on bronchial asthma.
  • 1,8 cineole is a skin penetration enhancer and is also drying
  • 1,8 cineole is an analgesic and is anti-inflammatory to the muscular and respiratory systems
  • Ravensara, Rosemary ct cineole, and Eucalyptus species all contain high amounts of oxides
  • Use care when using 1,8 cineole with asthmatics, as it is possible to set off an attack, based on individual responses


  • Oils with a high amount of phenols are effective anti-infectious agents for use with acute infections and illnesses. Stimulates the immune system.
  • Oils containing anti-inflammatory phenols are often used as part of a blend with other oils for healing the skin.
  • Is considered rubifacient and causes minor redness and skin irritation; increases local blood circulation; and has a local analgesic effect.
  • Oils high in phenols are considered to be the most irritating to the skin and mucous membranes. Generally, not safe used in a bath.
  • Wintergreen, Clove, and Tea Tree all have high phenol concentrations


  • Monoterpenols contain a large percentage of alcohol, which make them powerful anti-infectious agents because they can be antibacterial, antifungal and in some cases antiviral.
  • Monoterpenols are non-toxic, as well as mild on the skin and mucous membranes.
  • Beneficial for long term support of the immune system.
  • Linalol, a chemical component, has been found to be effective against bacteria.
  • Geraniol, another chemical component, has been found to be effective against fungi.
  • Research also shows that terpinene-4-ol in Tea Tree activates white blood cells that deal with infections.
  • Antispasmodic components of monoterpenols include geraniol, linalol, menthol, citronellol and borneol.
  • Oils high in monoterpenols are beneficial for use in skin care, as they have antiseptic and anti-inflammatory properties, as well as being safe and healing to the skin.
  • Monoterpenols are nervous system tonics, as well as emotionally balancing and detoxifying the immune system.
  • Lavender and Rosewood both contain linalol, which has a sedating quality, and is ideal to use in insomnia blends.
  • Geranium, Lavender, and Bergamot have a natural deodorizing effect because they inhibit bacteria.
  • With the exception of Peppermint, most monoterpenol rich oils are safe on the skin and are not known irritants.     


  • The therapeutic properties of oils containing high amounts of sesquiterpenols are varied.
  • Many oils high in sesquiterpenols are considered to be grounding, antispasmodic, antibacterial, skin healing, and anti-inflammatory.
  • Some of these oils offer long-term support for the terrain, act as tonics for the veins and lymph system, and are immune stimulants.
  • Sesquiterpenols are generally safe and are not known skin irritants.

In conclusion, you now see how essential oils are much more than just pleasing aromas! Most noteworthy is that the use of essential oils is backed by solid science and even various research studies that have proven that they can assist in helping with many health challenges. The chemistry of essential oils is, indeed, a wonderful world to explore. And, even if you don’t understand it, you certainly can appreciate its validity!

To see BioSource Naturals’entire collection of essential oil blends for body, mind, and spirit, click here

Read more about the physical and emotional benefits of essential oils here.

*This statement has not been evaluated by the FDA and is not intended to diagnose, treat, or prevent any disease.