Essential Oil Safety: 50 Hazardous Essential Oils To Avoid

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Essential Oil Safety: 50 Hazardous Essential Oils To Avoid

You have probably heard the term Aromatherapy and wondered what exactly that funny word, ‘aromatherapy’ actually means. It is the use of plant oils in their most essential form to promote both mental and physical well-being.

The use of the word aroma implies the process of inhaling the scents from these oils into your lungs for therapeutic benefit. If you have ever used a vapor rub for a cough then you have tried aromatherapy, although not in its purest form.

As a matter of fact, you probably have been using aromatherapy on yourself and your family for many years without realizing it through vapor rubs or electric vaporizers.

Vicks or other brands of vapor rub use eucalyptus or menthol to clear out stuffy chests and noses. Imagine if you used the undiluted essential oil of eucalyptus how clear your lungs would feel.

The term aromatherapy is generally new, beginning to be used in the 20th century, but the practice has been around for thousands of years. It is believed that the Chinese were one of the first cultures to use the scents of plants to promote health through the burning of incense.

Ancient Egyptians used distilled cedarwood oil mixed with clove, cinnamon, nutmeg, and myrrh to embalm the deceased. The Egyptians also used oils to perfume both men and women.

In the 14th century when the bubonic plague hit, killing thousands of people, aromas were used to ward off the deadly disease. There is even discussion that the popular nursery rhyme, “Ring Around the Roses” refers to aromatherapy.

The lines, “a pocket full of posies” allegedly refers to keeping the flower in one’s pocket in an attempt to keep the illness away.  Moving forward through later centuries a growth in books about the use of oils in healing grew.

The Greek alchemist, Paracelsus, used the term “essence” and focused study on the use of plants for healing purposes. While the use of essential oils for perfume continued to grow throughout the ages its’ use for medicinal purposes waned slightly until around 1928.

It was at that time that a French chemist named Rene-Maurice Gattefosse accidentally discovered the use of lavender essential oil to heal wounds. The story is told that he burned his forearm and reflexively placed it in the closest liquid he saw, which was lavender essential oil.

He was surprised to find that the burn healed rapidly and left no scar. It was then that he began using the term aromatherapy and wrote about the powers of essential oils.

Today, many people are trying to get back to nature. People have seen first- hand the dangerous effects of synthetic chemicals and processed medications. The use of all-natural essential oils for medicinal, cosmetic, and therapy purposes continues to grow.

Many people have found the results of using aromatherapy to be far greater than manmade medications and with far fewer negative side effects. Aromatherapy can be used by itself or in conjunction with typical medical treatments.  For example, you may use aromatherapy to ease pain after a surgical procedure.

You still get the benefit of the surgery but do not have to take the powerful and often dangerous pain medications that a doctor prescribes. 

Quality and Safety Control

Essential oils that are used in aromatherapy are not always easy to find. The Food and Drug Administration does not regulate essential oils so you, the consumer, will have to carefully read the ingredients of any oil you purchase to make sure that it is in its purest form.

In order to get the most benefit from aromatherapy, oils in their purest form should be used.

Finding the Best Essential Oils

Try to avoid synthetic oils. Essential oils are the only way to get therapeutic benefits from aromatherapy. They will not be cheap nor should many different kinds of oils be priced the same as the process of distilling them is varied.

Light exposure decreases the ability of essential oil to work, so only buy oils that are sold in dark bottles. The term “oil” is often a misnomer as many of them are not at all oily. To test how distilled oil is…try dropping it on a piece of paper to see if it dissolves quickly and does not leave an oil spot.

If you have a health store in your area shop there instead of a perfume store. It is more likely that they will have real essential oils for sale.

Safety when using Essential Oils

Essential oils are very powerful when they are not diluted. In order to make them safe, you should dilute them with a carrier oil. Ask at your local health store which carrier oils they have available as there are many from which to choose.

Follow the instructions carefully when making any essential oil compound. If a recipe says one drop, use only one drop. Anyone who has a nut allergy should also avoid carrier oils derived from nuts.

Oils should be stored out of children’s reach. If accidental ingestion occurs contact poison control immediately. Pregnant women should consult their physician before partaking in any kind of aromatherapy.

If you plan to use aromatherapy on infants or the elderly it is recommended that you use lesser amounts of oil in your recipe. Check with your physician to ensure that it is safe to use on a particular age group.

Some oils can be toxic if ingested even in small amounts. In general, unless specified for oral use, essential oils should not be ingested. Essential oils stored in a cool dry place, and tightly capped will last six to twelve months.

It is important to keep as little oxygen in contact with the oils as possible, so you will want to store them in full bottles, stepping down the bottle size as needed.

Essential oils should never be put on your skin in their undiluted form. They can irritate your skin quickly and cause a chain reaction that will make you sensitive to that oil for a lifetime.

Persons with asthma, epilepsy, or other serious health conditions should contact their physician before using aromatherapy. To avoid an allergic reaction, place a small amount of diluted oil on a patch of your skin. Cover the spot with a band-aid and wait a full day to see if irritation occurs.

This can avoid a potentially large allergic reaction to essential oils. Essential oils should be kept away from open flame or fire hazards as they are all flammable. Never use any sort of oil near your eyes. Wash your hands thoroughly after handling essential oils to avoid contact with your eyes or mouth. 

Hazardous Essential Oils

Some essential oils are very dangerous. These oils should not be sold at all, but can still be purchased over the internet or at less reputable shops. Others may be safe in some instances but can be rather dangerous if used in certain circumstances.

Before you take on an aromatherapy plan, take time to understand which oils are safe. Keep in mind that just because something is all-natural does not necessarily mean that it is not hazardous to your health.

  • Rosemary, common sage, hyssop, and thyme should never be used if you have high blood pressure.
  • Sweet fennel, hyssop, sage, and rosemary should be avoided if you have epilepsy.
  • Diabetics should not use angelica.
  • Those who suffer from hypoglycemia should stay away from geranium
    Sufferers of kidney problems should be cautious if they use juniper, sandalwood, or coriander.
  • Expectant mothers should especially avoid juniper, hyssop, clary sage, peppermint, lemon, fennel, lemon verbana, rosemary, and wintergreen.
  • Clary sage should not be used while drinking as it will intensify the effects of the alcohol causing it to act like a narcotic.
  • Chamomile and marjoram should not be used while driving because they cause drowsiness.
  • Some oils can cause allergies, such as citronella, clary sage, ylang-ylang, and verbana oils.
  • Oils that are believed to be carcinogens are calamus and sassafras, which should be avoided by everyone.
  • Methyl salicyalte is the active ingredient in aspirin and sweet birch essential oil. If you use aspirin for medicinal purposes you should avoid it due to the risk of overdose. It should also be kept away from children as it smells sweet and is equally dangerous to them.

While the list above is oils that can be dangerous in certain situations there are other oils that should not be used in aromatherapy at all.

These oils can be caustic if inhaled and should be avoided at all costs. This is not a comprehensive list, you should do research on any oil you plan to use before you purchase it.

Oils that Should Not be used in Aromatherapy


It contains cyanide which even in small amounts can be lethal.


Skin irritant.


Can cause dizziness and heart irregularities


Phototoxic, severe sunburn could occur if it is exposed to sunlight.

Boldo Leaf

Produces convulsions even in small quantities.


It has carcinogenic (cancer-causing) properties and can cause kidney and liver damage.


Oral ingestion can be toxic.


Skin and mucus membrane irritant.

Cinnamon Bark

Skin irritant


Skin irritant


Classified as a serious skin irritant.


It can cause epileptic episodes.


Eye, skin, nose, and mucus membrane irritant.

Jaborandi Leaf

An oral toxin, skin irritant.


Skin and mucus membrane irritant.

Spanish Origanum

Skin and mucus membrane irritant

Dwarf Pine

Skin irritant.

Brazilian Sassafras

Banned by the FDA as a carcinogen and can be toxic even in small amounts.


Skin irritant.


Toxic to the skin and if taken orally.


It can cause convulsions, vomiting, uterine bleeding, and death as a result of an organ or respiratory failure.

Cedarleaf Thuja

Thuja Plicata

It can be a neurotoxin.


It can be a skin irritant, especially to those with aspirin sensitivity. The oil itself is poisonous.


Toxic to the liver and kidneys suppresses heart function.


Consumption can cause visual and auditory hallucinations and addiction. It can also cause convulsions and be a neurotoxin.

There are some essential oils that are highly toxic and should never be used in any circumstance.

Essential Oils to Completely Avoid

  • Mugwort
  • Pennyroyal
  • Rue
  • Sage
Herbal Guide Staff

The Complete Guide to Natural Healing believes that food, vitamins, supplements, and alternative medicine can be your best medicine. Our staff will show you the truth about health and wellness, so you can help your family and closest friends get even healthier. You’ll learn exactly what you should do and how to eat to get healthy, exercise to get your leanest, healthiest body and how to take control of your family’s health, using natural remedies as medicine.



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