hidden dangers of essential oils

What are the Hidden Dangers of Essential Oils? (Toxicity and Precautions)

Generally speaking, essential oils are split between non-toxic and toxic. There are a few common essential oils that everybody likes and uses. Then there are other “dangerous and toxic essential oilsthat people don’t know a lot about. But what are those hidden dangers of essential oils that we must be aware of? Because let me tell you, in big doses, some essential oils can even be lethal.


Nonetheless, those toxic essential oils are also full of benefits. With a proper research, the dangers of essential oils would not be a mystery anymore. This fact would no longer make them so scary and misunderstood.


The IFA (International Federation of Aromatherapists) made a list of essential oils that are not allowed to be used on the skin. The list is there to protect the majority of people that uses them, with or without a doctor’s consent.


The issue of toxic essential oils is a hot topic. Usually, most essential oil practitioners avoid using those few essential oils that are toxic. But can they be dangerous?


This article is about facts and case studies on various toxic essential oils. I will also give you a few examples and details on some dangerous essences. My goal is to help you understand this particular topic and make informed decisions from now on.


Aromatherapy is the practice of using essential oils. There are many studies performed on a lot of essential oils. Because of that, their compounds are well-known to scientists. But, the general Aromatherapy training does not pay too much attention to this aspect.


Instead, they focus on using the lowest doses to be safe or avoid law suits. Whatever the reason, we could be losing a lot of knowledge without exploring all the dangers of essential oils.


IFA’s List of Hazardous Essential Oils Contains:

  • Cinnamon Bark essential oil
  • Oregano essential oil
  • Clove essential oil
  • Ajowan essential oil
  • Mountain Savory essential oil
  • Cassia essential oil

Other Potentially Toxic Essential Oils:

  • Pennyroyal
  • Tansy
  • Wormwood
  • Calamus
  • Wormseed
  • Wintergreen
  • Arnica
  • Boldo
  • Horseradish
  • Mustard
  • Rue
  • Mugwort
  • Sassafras
  • Savin
  • Oak Moss
  • Cumin
  • And Camphor.


Did you know that in France, specialized doctors actually prescribe essential oils as drugs?


It took many years of experiments, but the French found a good way to prescribe the right doses to their patients. They’ve also found a way to avoid many of these dangers of essential oils.


Even if they are toxic in a large dose, it’s just like using venom to treat a disease or illness. Everybody knows you can’t drink the venom. But small doses can help fighting certain viruses, diseases and bacteria. And that makes the venom extremely useful just like those few toxic essential oils.


The Symptoms of a Toxic Essential Oil Poisoning:

  • Headaches
  • Irritation and skin redness
  • Dizziness
  • Nausea
  • Lethargy
  • Epilepsy
  • Fainting
  • Coldness in hands and feet
  • Cardiac arrest
  • Respiratory depression
  • And even coma and death.




The dangers of essential oils are not that many, but they are serious if not treated with enough attention. An essential oils acute toxicity happens only when taken internally, in a large dose. That’s when they reach the blood and other organs the fastest and saturate them.


Such a large dose may vary from 5 grams, 20 grams to 300 grams, depending on the essential oil.


The absorption methods are also important for essential oils safety. Taking an essential oil internally, is the fastest method to get instant results. The second most effective absorption method is through the intimate areas. These practices however, are not to be used without medical supervision. 


Then, we have the topical applications. Many external factors can influence the skin absorption. Most important ones are:

  • Heat,
  • Active ingredients of the essential oil,
  • A person’s health condition.


Inhaling is one safe method, with the lowest risks. Aromatherapy uses small doses and it’s a well-known fact that essential oils evaporate. These things make their inhalation as safe as can be.


If you want to find out more about all the precaution measures to take when using essential oils, please continue reading.


The dangers of essential oils spread even to those considered safe oils. Here’s an example of a near fatal case of oil ingestion:


It is a good example of a popular and beneficial essential oil with low toxicity: Peppermint essential oil (Mentha Piperita).

Dangers of Essential Oils


It is good for treating early symptoms of a cold, a headache or an irritable bowel syndrome, etc.


Its active compounds are menthone and menthol, which give the oil its minty odor. Then, there are the pulegone and cineole among others. They all have analgesic and antiseptic effects.


But when ingested in a large dose, Peppermint essential oil is toxic and dangerous. This one patient, a 40 –year old woman went to a hospital in a coma. She was barely breathing. Her whole body smelled of Peppermint oil.


The doctors intubated her and she went through gastric lavage among many other treatments. She was finally able to respond to her name in 24 hours after the emergency treatment. Read more about this case here.


This is a good example on how a large dose of a usually harmless essential oil can turn into a serious health or life threat. The dangers of essential oils are real! And this is why large doses of essential oils are not recommended by most Aromatherapists.


Dangers of Essential Oils: Application Methods and Dosage


Generally speaking, most Aromatherapists recommend small doses of 2 – 2, 5% in skin applications. If the skin is not covered (with a band aid, fabric or plastic wrap etc.), the essential oils will not be fully absorbed into the skin.


American studies show that only 75% from a dose of different essential oils is absorbed into the skin. This percentage applies only when the skin gets covered after the massage. If the skin was not covered, the amount of absorbed essential oil was of only 4%.


The amount of essential oil absorbed through the skin and into the blood is influenced by a few factors:

  • The temperature of the body.
  • The type of compounds found in an essential oil.
  • The carrier oil used.
  • The absorption method, etc.


Studies show that only 2% of the citrus essential oils (containing d-limonene) get absorbed into the skin.


Case Study I:


This study involved a human volunteer meant to find out the effects of Lavender essential oil. The volunteer had to massage a 2% dilution of Lavender essential oil into his skin. They noticed the absorption was fast.


10% of the essential oil went straight into the blood circulation in 20 minutes. In 90 minutes, it was completely absorbed into the body.


Case Study II:


A nourishing body lotion with Ylang Ylang was spread onto several rhesus monkeys. Because a lot of hair covers the monkeys’ skin, the results showed that 20%-70% of the lotion was absorbed.


This experiment shows that essential oils are better absorbed through hair follicles.


But if there is any damage on the skin (bruises, scars, dermatitis, burns etc.), it is best to consider a 100% absorption rate. So, be careful not to use more than the recommended dose.


How a Toxic Essential Oil Can Also Be Beneficial


Among the dangers of essential oils, we have the Wintergreen essential oil. It is known to have caused many deaths in the past, so it’s not recommended in therapy use.


The toxicity of essential oils is also measured within the limitations of the median lethal dose. This median lethal dose is usually given by tests on lab rats. A 1.0 median lethal dose in essential oils means that half of the rats’ population has died after ingesting 1 gram (0. 035 ounces) per 1 kg (or 2. 20 pounds) of body weight.


Wintergreen essential oil contains methyl salicylate, the same substance found in aspirin. An estimation of the median lethal dose of Wintergreen in humans is 18 grams (0.63 ounces) for an adult that weighs 60 kilograms (132 pounds).


To treat a sore back you would need a 2.5% dilution of Wintergreen essential oil. A 1 mL (0.033 fl. oz.) blend would be enough to take the pain away.


1 mL (0.033 fl. oz.) of a blend that contains Wintergreen would be around 0.025 grams. The math is simple: 1mL x 25% = 0.025 grams


0.025 grams from the 18 grams of the lethal dose = 0.00139. This means the quantity of Wintergreen you apply for your sore back is only 0.139% of the lethal dose. In other words around 700 times less than the lethal dose.


This is how we can use in a safe manner some of the toxic essential oils. They are a threat to our health only in high doses. If you always follow the application method and dose, almost any toxic essential oil can be safe to use. Considering you’ve consulted a medic first, especially if you suffer from certain conditions.


Methyl salicylate (found in the Wintergreen EO) is NOT recommended to people that take Warfarin, which keeps the blood from clotting. Not recommended for skin application either!


The reasonable thing to say after all the examples so far, is that all essential oils are toxic in some degree. Especially when used in large doses.


There are also a few essential oils out there that have a higher level of toxicity. Those are the ones that need a bit of extra care and research every time you want to use them.


Essential oil safety is simple when you follow the exact advice of a specialist or a trusted source. But you also have to do your own research to find out more about a certain essential oil you want to use.


You are now able to recognize the symptoms of an essential oil poisoning. But you can also recognize the dangers of essential oils or the toxic essential oils that you need to pay attention to.


You also have a few case studies done on essential oils so far. And you can calculate the amount of essential oil needed to use to be safe, if you wish to.


Remember that all toxic essential oils are named so because they’re mostly misunderstood. But also because there’s not enough literature on all their exact effects and properties.


Have you ever done some in-depth research for a certain essential oil that you wanted to use but heard it was toxic? Did you end up using it?


My advice, whenever you’re considering taking essential oils internally, is to talk to a doctor first. Then find a reliable source to read or buy from.


In a really small dose, they can help with various ailments and health conditions. If you’re lucky to have found good and skilled Aromatherapy specialists, keep them close. Their advice is always precious especially when you’re in doubt.



Join the Essential Bazaar Newsletter

Signup now and receive an email once I publish new content.

I will never give away, trade or sell your email address. You can unsubscribe at any time.

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.