Aromatherapy – Probably Useless, Perhaps Even Dangerous

girl with leaves over her eyes

Essential oils for aromatherapy has become rather popular in recent time, the ‘essence’ of all that good stuff in plants captured and inhaled to treat diseases. However, there is little evidence supporting aromatherapy as a form of medication, while the dangers of the concentrated chemicals in essential oils are rarely publicized. Don’t let plants (and crooked businesspeople) pull their leaves over your eyes.

What are Essential Oils?

An ‘essential oil’ is a term encompassing non-water-soluble chemicals from a plant source (alcohols, aldehydes, esters, and other hydrocarbon derivatives) that usually bear its characteristic odor. The plant produces these chemicals to deter predators, attract pollinators, or even as a response to ‘pain’ to warn their plant neighbors!

list compounds functional groups essential oils
Some of the compounds present in essential oils listed by their functional groups1.

Essential oils are named as such because the ‘essence’ of a plant is collected from the raw stock. These chemicals are usually strong-smelling, as chemical extraction techniques like distillation allow them to be concentrated 200 to 300 times their natural state by weight2. As with any other chemical, increasing its concentration magnifies its potency, and hence its effects.

Essential oils have been used in aromatherapy for thousands of years as a form of odor therapy – breathing in the vaporized oils for medical benefit. Today it is considered an alternative (non-conventional) form of treatment because – at the time of writing – there is little to no evidence supporting its efficacy3.

Popularity of Aromatherapy

Despite the lack of evidence, people continue to believe that aromatherapy has therapeutic benefits. Many sources substantiate claims that these oils have helped with an impressive array of other diseases ranging from colds and aches, to deadly diseases such as cancer. The situation isn’t helped by news outlets and social media propagating such false claims, good intentions notwithstanding.

Its rise in popularity can also be attributed to their ease of access; there are countless businesses selling hundreds of essential oils for aromatherapy. Just as with alkaline water (another marketing scam), as long as the manufacturers don’t directly market it by claiming therapeutic benefit, regulatory authorities cannot restrict sales.

Today one can also simply order a distillation kit, find some instructions online and then pluck up a few plants in their backyard to extract their own essential oils.

aromatherapy business ad social media
Sure, companies can’t market their products directly as therapeutics, but on social media they’re allowed to run wild with their claims. Look at this one go.

The situation isn’t helped when advocates for alternative treatments include celebrities and prominent figures in authority. One internationally recognized ‘authority’ responsible for the promotion of essential oils and aromatherapy is David Stewart, mainly because of his book ‘The Chemistry of Essential Oils Made Simple: God’s Love Manifest in Molecules’.

If some guy with a Ph.D. writes a book, then it MUST be based on evidence-based science and research /s

Dr. Stewart quite ingeniously makes essential oils ‘simple’ by declaring that a chemical compound made in a laboratory isn’t the same as an identical one made in nature. This is similar to the flawed argument that engineered genes aren’t the same as genes that have evolved over time. This basically gives him free rein to bestow beneficial health claims on essential oils without worrying about existing chemical literature, very convenient indeed.

Well, it’s certainly not the only time an academic authority has made claims not supported by scientific evidence. And let’s not get started celebrities like Oprah Winfrey, who spews so much quackery that she deserves her own pseudoscience blog altogether.

Dangers of Aromatherapy

‘Surely if it comes from a plant it can’t be harmful. After all, fruits and vegetables are healthy!’ Despite claims that plant-derived compounds are ‘natural’ and can’t harm the human body, it doesn’t take a genius to figure this one out. Whether a molecule is synthesized in the lab or in nature makes no difference to its properties, it is simply that – a molecule.

‘Natural’ vs ‘Synthetic’

A key argument by the proponents of aromatherapy is that natural products from a plant are much safer than the same compounds made in a laboratory. This is similar to the flawed argument that engineered genes aren’t the same as genes that have evolved over time.

Plants have ingenious metabolic pathways that allow them to produce the most intricate of molecules, shaped by millions of years of evolution under resource constraints. Some of these have indeed been isolated and developed for their medicinal purposes, one of the most iconic being paclitaxel, a potent anticancer compound that was first extracted from the bark of the Pacific yew tree.

Paclitaxel has also since been synthesized by chemists via many different pathways and is now produced on a massive scale using plant cell cultures4. Many different approaches, the exact same molecule.

To cement the fact that natural products can be dangerous too, an individual died after ingesting aforementioned yew leaves containing paclitaxel. Chemicals are chemicals, regardless of their ‘natural’ status5.

Health Dangers

Apart from being volatile compounds with relatively low flash points, there is an increasing amount of evidence that essential oils may actually be harmful to human health. Studies have shown that certain oils are unsafe – phototoxic, allergenic and even endocrine-disrupting, causing male breast tissue growth in individuals exposed to lavender and tea tree oil6,7.

Because they are not considered ‘medicines’, the safety and effectiveness of essential oils are not regulated by health agencies. The lack of clinical trials altogether means using essential oils as medication is risking adverse health effects, not to mention the absence of any evidence of benefits.

essential oil bottle in hand
Because they aren’t classified as medicines, manufacturers of essential oils are not required to submit toxicology profiles to health authorities. Remember thalidomide? Enough said.

Furthermore, patients who turn to aromatherapy and other alternative treatments show a decrease in or even discontinuation of their conventional, science-based medication. In potentially curable cancers, refusing chemotherapy in favor of alternative medicine has been shown to double the risk of death8.

As of right now, peer-reviewed evidence shows that aromatherapy and essential oils have no conceivable benefit bar placebo. Indeed, many real medicines today are isolated and purified from plant sources, but these compounds have been thoroughly researched to ensure their benefits outweigh their adverse effects.

It is important to remember that just because essential oils are made by plants, there are still no guarantees on their safety.


  1. Sadgrove, N., & Jones, G. (2015). A contemporary introduction to essential oils: chemistry, bioactivity and prospects for Australian agriculture. Agriculture, 5(1), 48-102.
  2. Cassel, E., Vargas, R. M. F., Martinez, N., Lorenzo, D., & Dellacassa, E. (2009). Steam distillation modeling for essential oil extraction process. Industrial crops and products, 29(1), 171-176.
  3. Lee, M. S., Choi, J., Posadzki, P., & Ernst, E. (2012). Aromatherapy for health care: an overview of systematic reviews. Maturitas, 71(3), 257-260.
  4. Mountford, P. G. (2010). The taxol story development of a green synthesis via plant cell fermentation. Green Chem Pharmaceut Ind.
  5. Grobosch, T., Schwarze, B., Stoecklein, D., & Binscheck, T. (2012). Fatal poisoning with Taxus baccata. Quantification of Paclitaxel (taxol A), 10-Deacetyltaxol, Baccatin III, 10-Deacetylbaccatin III, Cephalomannine (taxol B), and 3, 5-Dimethoxyphenol in Body Fluids by Liquid Chromatography – Tandem Mass Spectrometry. Journal of analytical toxicology, 36(1), 36-43.
  6. Lis-Balchin, M. (1999). Possible health and safety problems in the use of novel plant essential oils and extracts in aromatherapy. The journal of the Royal Society for the Promotion of Health, 119(4), 240-243.
  7. Henley, D. V., Lipson, N., Korach, K. S., & Bloch, C. A. (2007). Prepubertal gynecomastia linked to lavender and tea tree oils. New England Journal of Medicine, 356(5), 479-485.
  8. Johnson, S. B., Park, H. S., Gross, C. P., & James, B. Y. (2018). Complementary Medicine, Refusal of Conventional Cancer Therapy, and Survival Among Patients With Curable Cancers. JAMA oncology.

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