Antimicrobial Efficacy of Essential Oils & How to Use Them

By Dr. Justin Marchegiani

Essential oils are aromatic compounds extracted from plants, commonly through steam distillation or cold pressed methods. An essential oil from one plant may contain anywhere from a dozen to several hundred individual compounds. Even trace amounts of these components are important pieces of what makes each oil unique.

History of Essential Oils

Essential oils have been used across the world for centuries. Ancient Egypt is commonly referred to as the birthplace of essential oils, where these plant extracts were used for cosmetic and medical purposes as early as 4500 BC. Aromatherapeutic uses of essential oils in traditional Chinese medicine date back to the period between 3000 and 2000 BC. 

Efficacy of Essential Oils

Just about every essential oil has antimicrobial properties and have been scientifically proven to demonstrate anti-fungal, anti-bacterial, and anti-viral activity. In fact, essential oils have even been efficient in fighting drug resistant strains which conventional antibiotics have failed to treat! 

In fungal pathogens, essential oils are able to cross the cell wall and disrupt ATP assembly. In bacterial infections, essential oils destabilize and help break down the membrane integrity. Essential oils have antiviral activity against RNA and DNA viruses, such as herpes (types 1 and 2), dengue virus, influenza (the flu), poliovirus, and coxsackievirus (hand, foot, and mouth disease). 

Lemongrass, eucalyptus, peppermint and orange oils were tested against 22 bacteria, including Gram-positive and Gram-negative– they were effective against all 22 bacterial strains.

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Oregano, thyme, clove, lavender, clary sage, and arborvitae were effective against the bactiera Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis, Bacillus cereus, Arthrobacter protophormiae, Pseudomonas fragi, and fungi Chaetomium globosum, Penicillium chrysogenum, Cladosporium cladosporoides, Alternaria alternata, and Aspergillus fumigatus.

How to use Essential Oils


  • Neat: Before using an essential oil, be sure to check if it needs to be diluted. Some oils can be used neat (undiluted), while others are very strong and need to be cut with a ‘carrier oil’ to dilute the oil. If your oil can be used neat, one or two drops is enough to do the trick! Examples of when you may use an oil neat: zits, blemishes, cuts, scars, burns, mosquito bite, or even as a perfume!
  • Topically: For nicks and cuts, using an antibacterial essential oil can help cleanse the wound and prevent infection.
    • Antiseptic oils include:
      • Tea tree: A very powerful oil, tea tree can establish a very strong barrier to prevent bacterial and viral invaders from entering the bloodstream.
      • Myrrh: Myrrh was used by Greek soldiers in the battlefield to disinfect wounds and stop bleeding!
      • Lavender: Lavender is a more gentle oil which is great for kids, and can be used neat (no dilution). In addition to disinfecting the wound, it is a very soothing oil which can also soothe pain, burning, or stinging sensations.
  • Diluted: Carrier oil options for your diluted oils include:
      • Olive oil
      • Coconut oil, or fractionated coconut oil
      • Jojoba oil
      • Cacao butter
      • Rosehip oil
      • Red raspberry seed oil
    • You may also use vodka or vinegar for a spray (perfume or household cleaner). Aloe vera is a great carrier for lavender to use on burns and bites!
  • Steaming: Inhaling oils can clear the lungs and invigorate the body. I like to diffuse calming oils at night and stimulating oils during the day while I work.
    • Shower: Try dropping 2-3 drops in the shower and allowing the hot water to create an intoxicating steam!
    • Diffuser: A mist diffuser uses cold water to disperse the oil for a few hours.
    • Stove: You can even add a few drops to a pot of water and allow it to simmer on the stovetop.
    • Fabric: Try dropping a relaxing oil on your pillow to help you drift off into dreamland.


With the overuse of antibiotics leading to a rise in drug resistant strains of bacteria, essential oils offer a natural and effective treatment. Essential oils should be considered as an effective cleaning agent in household cleaners, and as a holistic treatment for fungal, bacterial, and viral infections.

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The entire contents of this website are based upon the opinions of Dr. Justin Marchegiani unless otherwise noted. Individual articles are based upon the opinions of the respective author, who retains copyright as marked. The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. It is intended as a sharing of knowledge and information from the research and experience of Dr. Justin and his community. Dr. Justin encourages you to make your own health care decisions based upon your research and in partnership with a qualified healthcare professional. These statements have not been evaluated by the Food and Drug Administration. Dr. Marchegiani’s products are not intended to diagnose, treat, cure or prevent any disease. If you are pregnant, nursing, taking medication, or have a medical condition, consult your physician before using any products.