Essential Oils - Safe or Hazardous?

Essential oils are all the rage.

The miracles of essential oils and people selling them have come to my attention. Many people claiming the therapeutic benefits of essential oils say they are the answer to all that ails us. Several friends and a few clients have asked me what I think about the topical, aromatic and internal use of essential oils.

Years ago, I gave it some thought and even tried several. I used a diffuser to fill the room with my favorite scents, like lavender and rose. I considered the oils mentioned in the Bible, like Frankincense. My past experience with medicinal herbs alerted me to the volatile oils in plants and the dangers they can pose to health when taken for more than two weeks or too often.


Essential oil is a natural oil typically obtained by distillation and having the characteristic fragrance of the plant or other source from which it is extracted. Essential oils are used as flavoring, fragrance, aromatherapy, and for medicinal purposes, depending on the type of oil.
Fragrance is the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form.
Toxin is an antigenic (induces an immune response in the body) poison of plant origin.
Phytochemicals are biologically active compounds found in plants, typically utilized as a toxin to deter or kill anything that would eat it or to protect the plant from harsh elements, like too much sun (photosensitivity).
Solvent is a liquid, other than water, that acts to weaken and dissolve other substances

The underestimated power of essential oils

The use of water or alcohol to make a plant extract for use in herbal medicine and the essential oil derived from that plant are not the same thing. Essential oils are concentrated volatile and fat-soluble, so they are different from the mainly water-soluble whole plant extracts used in herbal medicine. One drop of peppermint oil is equivalent to 28 cups of peppermint tea. Essential oils are toxic because of their high concentration, but also because of their ability to pass across membranes very efficiently due to their ability to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Essential oils are extremely potent plant compounds that can have a very dramatic effect on the body.

Plant properties are concentrated in its oils. 256 pounds of peppermint leaf makes one pound of peppermint essential oil and 1,000 pounds of roses are needed to make one pound of rose essential oil.
Example: Peppermint is best known for its flavoring and fragrance properties. Peppermint leaves are one of the most widely consumed single ingredients of herbal teas. The essential oil extracted from peppermint leaves is used in many food, cosmetic and pharmaceutical products.
• Peppermint contains the phenolic acid - salicylic acid, which is a beta hydroxy acid. Salicylic acid is used as a food preservative, antiseptic and bactericide, as a medicine and is an important active metabolite of aspirin. Topically, salicylic acid is capable of penetrating and breaking down fats and lipids, causing moderate chemical burns in the skin. If the solvent is alcohol, acetone or oil, it may damage the lining of pores. OTC limits of 2% are set for topical preparations, like acne treatments, while 27% is used for wart removal. The salicylic acid content of peppermint candies and tea is reportedly very high. Imagine how high the salicylic acid content of peppermint essential oil is! More frequent use may lead to an increase in side-effects without an increase in efficacy. When ingested, salicylic acid inhibits prestin (a protein that is critical to sensitive hearing in mammals), producing an ototoxic effect resulting in hearing loss. Overdose can lead to salicylate intoxication, which presents clinically in a state of metabolic acidosis with compensatory respiratory alkalosis. If unchecked, metabolic acidosis leads to acidemia (a low body pH with serious consequences, including coma and death). Respiratory acidosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35-7.45) with a concurrent reduction in arterial levels of carbon dioxide. These conditions are two of the four basic categories of disruption of acid-base homeostasis. Some people are hypersensitive to salicylic acid. Salicylic acid is photosensitive on sun-exposed areas of the skin. Salicylic acid is associated with Reye's (Ryes) syndrome, which is a rare but serious condition that causes swelling in the liver and brain. Symptoms include vomiting, lethargy, nightmares, headaches, hyperactive reflexes, respiratory arrest, cerebral edema, coma, personality changes, confusion, seizures and loss of consciousness, liver toxicity, brain damage and has a 20-40% mortality rate.
• Peppermint also contains rosmarinic acid, a potential anxiolytic (psychoactive compound that inhibits anxiety and is responsible for its relaxing effects), which iinhibits GABA transaminase enzyme. GABA transaminase enzyme catalyzes chemical reactions. Other GABA transaminase enzyme inhibitors include Valproic acid (anti-epileptic medication), Vigabatrin (suicide inhibitor), Phenylethylidenehydrazine (antidepressant), Seromycin (antibiotic) and analgesics or painkillers, like morphine. Peppermint could increase the effects of these medications.
• Both Salicylic acid and Rosmarinic acid have non steroidal anti-inflammatory effects, like NSAIDs and acetaminophen - acting on the peripheral and central nervous systems.
• Peppermint essential oil induces mutations.
• Peppermint tea can calm an upset stomach, ease tension headaches and alleviate the symptoms of IBS, but peppermint oil should never be applied to the skin.
• Peppermint oil can cause life-threatening breathing problems, especially in infants.
• Peppermint oil can interact with cyclosporine, drugs that treat diabetes, high blood pressure medication and will cancel out the beneficial effects of homeopathic remedies.

The toxicity of essential oils does not entirely depend on high concentrations. Many essential oils are inherently toxic at very low concentrations due to the very toxic components contained in them. Other factors that affect toxicity include the age of the user and their weight, personal body chemistry and the efficiency of their metabolism, personal history, previous sensitization to essential oils containing similar components or some adulterant in the oil, olfactory, topical or oral use, the influence of other medications, both pharmaceutical and herbal, household and body care products, cosmetics and perfumes, air fresheners, foods and beverages consumed. The use of very small doses of essential oils over many months or years can have toxic effects. For example, massage therapists who use oils, lotions and creams containing essential oils have been affected by sensitization, as evidenced by the prevalence of hand dermatitis.

Rosemary oil stimulates hair growth, is a remedy for indigestion, hair loss, and muscle and joint pain. Rosemary oil is toxic if ingested. It should never be used by people with high blood pressure, ulcers, Crohn’s or Colitis. Rosemary interacts with anti platelet and anticoagulant drugs, ACE inhibitors, diuretics, lithium, and can interfere with certain diabetic medications.

Eucalyptus Oil is a popular ingredient in cold and flu medications. It has been used to treat diabetes, relieve breathing problems and congestion, and arthritis. Eucalyptus should be avoided by children, pregnant and lactating women, and by people who are taking 5-fluorouracil. Eucalyptus can trigger an asthma attack. Eucalyptus will cancel out all benefits of taking any homeopathic remedy.

Essential oils are not safe for pets.

Natural is safe?

There is a misconception that because all herbs are natural, they are therefore ‘safe’. It is assumed that the occasional mistake is never injurious, but instead provides valuable guidance in the correct use of essential oils. If errors are made in the use of essential oils, people believe they may be resolved by discontinuing use of the oil without causing any damage. Plants contain potent phytochemicals that can be poisonous. Example: Mistakes in identifying and consuming various wild edible plants have killed people. They definitely discontinued use of the offending plant when it made them sick, but the damage was done and they died. My example illustrates how faulty that reasoning can be.

Do not take essential oils by mouth!

The dangers of using essential oils, especially internally include, but are not limited to, severe itching and skin rashes, fatal poisoning from ingesting the wrong oil, and toxicity from adulterated oils. Oils like pennyroyal and wintergreen can be fatal if swallowed. Taking essential oils internally may not cause immediate illness or death, but the toxins in oils can burn the intestinal epithelium and cause serious GI tract damage.

Those who profit from the essential oil industry will list the beneficial effects on the skin and other organs and tissues, while blaming reactions to their products on the clients themselves. Such testimonies are bias. Don’t take your friend’s word for it, even if they sell essential oils. Aromatherapy training requires 200 + hours of classes, which includes the study of chemistry. Even if you are consulting with an “expert,” it’s best never to take essential oils internally. There are things about the micro biome of the intestines and the structure of the GI tract that the aromatherapist or other professional does not know. A sales rep may advise adding drops of citrus oil to drinking water.

There was a time when I used aromatherapy and it took a while for me to connect the increasing inflammation in my lungs and developing respiratory problems with the use of a diffuser. Lavender is in my deodorant, but upon considering ingestion of essential oils, my intuition begged me to do some research and body wisdom said, “Stay away from that!”

Drug metabolizing enzyme system

Drugs, solvents, pesticides and herbicides are xenobiotic (stranger to living things) compounds foreign to normal biochemistry. A set of metabolic biotransformation pathways employ an elegant combination of cell membranes, that function as selectively permeable physical barriers, and low-specificity enzymatic systems to remove foreign and poisonous compounds from the complex mixture of chemicals during normal metabolism, modify their chemical structure, detoxify and then remove them from the body.

Drug metabolism is an important aspect of pharmacology and medicine. This also involves the rate of metabolism which determines the duration and intensity of a drug’s action in the body and hazardous drug interactions.

Drug metabolism is divided into three phases. Enzymes produced from the cytochrome P450 genes are involved in the formation (synthesis) and breakdown (metabolism) of various molecules and chemicals within cells. CYP450 enzymes are primarily found in the liver but some exist in the intestine, lungs, brain, and kidney.
Phase 1: Cytochrome P450 enzymes modify xenobiotic compounds by oxidation, often in the liver. If the metabolites of phase 1 reactions are sufficient, they may be excreted at this point, however most phase 1 products are not eliminated rapidly and undergo a subsequent reaction.
Phase 2: The modified compounds are then conjugated (combined with glucuronic acid, sulfate, or glycine) and then catalyzed by transferase enzymes, such as glutathione S-transferases (GSTs).
Phase 3: The conjugated xenobiotics are further processed before being excreted from the body.

• People who take in more than one drug metabolized through the CYP450 enzyme system increase the potential for experiencing drug-drug interaction (DDI) which changes the effectiveness and/or toxicity of one or all the drugs in the system. This can result in potentially dangerous side effects. Women have a higher prevalence for drug-drug exposure (DDE). The highest prevalence was in women age 45-64 and the second highest were women age 34-45. I think it is due to the fact that the older people get, the more medications they are prescribed. The most researched chemical interactions with herbs have been performed on St. John’s Wort.
• There is a potential for toxicity from essential oils, especially for people with impaired detoxification systems. Genetic testing has revealed that the CYP 450 enzyme detoxification pathway is impaired in 50% of Americans and this leads to toxicity issues, leading to drug interactions, and overdoses. Gut microbes directly affect gene expression and I think are connected to CYP450 enzyme impairment, which is likely due to deficient or absent beneficial bacteria in the gut.
• The CYP 450 pathway is needed for essential oils to be detoxified. Medication blood levels are altered whenever essential oils are used. In France, only medical doctors can prescribe essential oils internally. Depending on the herb, essential oils are the equivalent of 10-50 cups of herbal tea or twenty times the recommended dose of an herbal tincture.

Others have
MTHFR issues.

Most essential oils, antidepressants and 80% of pharmaceuticals are detoxified through the phase 1 pathway in the liver. When the intensity of the plant constituents interact with medication the results are disturbing, with the potential of causing harm. For example, the use of peppermint or eucalyptus in any form or concentration will nullify the effects of homeopathic remedies. Peppermint essential oil interact with a long list of medications.

Touted for their antibacterial, antimicrobial, antiviral and anti-fungal properties, essential oils can kill many types of beneficial and necessary bacteria in the gut. Studies of the antibacterial properties of essential oils compare them to antibiotics and suggest they are an effective alternative to antibiotics.

The liver is only able to metabolize so much and overload of this system results in xenobiotic toxic stress.

essential oils

Contaminants and adulterants

The International Organization for Standardization (ISO) intention of standardization was to make essential oils more consistent, but that encourages adulteration. People think, based on the packaging, that they are getting a pure oil, but adulterated oils are very common in the market to the lower cost of production, increase shelf life or augment the scent. Some essential oils are very unstable and may last for only a few months. Oils can become highly irritating when they’ve been kept on the shelf too long. Not all essential oil companies test their oils for quality.
• Essential oils are in topical body care products that also contain carriers to prevent absorbing too much. Adulterated oils used on the skin can cause or worsen skin conditions due to other chemicals in the oil. Only medicinal-grade oils are suitable for topical therapeutic use.
• Not all synthetic components are made the same way, which introduces the possibility of contamination with other chemicals, which changes the composition and therefore the adverse effects, making them worse. Synthetic components account for the increased toxicity of the essential oils purchased today, especially in the area of sensitization.
• Sensitizers are materials that increase the aroma of essential oils or the products that contain them. Essential oils have a known reputation for sensitization and being potential allergens. Sensitizers can cause severe skin and/or respiratory responses. Sensitization develops over time. Skin sensitizers can cause an allergic reaction, with redness, rash, itching, swelling or blisters at the point of contact or elsewhere in the body. Common skin sensitizers include, formaldehyde, methyl methacrylate and toluene diisocyanate. Respiratory sensitizers can at first cause symptoms similar to a cold or mild hay fever. However, eventually severe asthmatic symptoms can develop, including wheezing, chest tightness, shortness of breath, difficulty breathing and/or coughing. A severe attack can cause death. Examples of respiratory sensitizers are toluene diisocyanate, maleic anhydride, and latex. Some sensitizers have been shown to interact with other molecules, such as proteins, which indicated how immunogenicity occurs.
• ISO stipulates there be a named botanical source, but the actual plant source is often a hybrid, cultivar or clone obtained by micro-propagation (like tea tree), which may make them more toxic.

Many people have not thoroughly researched essential oils, their use and know exactly what they are getting.

Animal testing

In their innocence, advocates of essential oils claim that essential oils have not been tested on animals, but this contravenes the Trade Description Act and the Health and Safety regulations, as only essential oils tested on animals can be legally sold and used for foods, perfumes and cosmetics.
• Most essential oils were tested over 30 years ago, so the toxicity data is meaningless, as different essential oils are now used, some of which contain different quantities of synthetic components.
• More recent animal tests include essential oil components and further genotoxicity, mutagenicity and pharmacological evaluations on both essential oils and components.
• A major drawback of animal testing is trying to evaluate feelings - from mild headaches to brain-splitting migraines; feeling sick, vertigo, nausea, tinnitus, sadness to suicidal thoughts, anxiety, melancholia, feelings of hate or rage - which are clearly impossible to measure in animals.
• Testing on animals also disregards the possibility of modification by other substances, including food components, food additives, environmental toxins, etc.
• The detoxification process is the biotransformation of toxic substances by individual enzymes, which attack certain chemical groups. The process involves microsomal oxidation using CYP450 enzymes, followed by the conjugation phase and then possibly numerous biotransformations in the third phase, giving rise to hundreds of metabolites. The extrapolation from animal to human becomes difficult because the major metabolites may be entirely different. The major metabolites can be influenced by other components present, which can affect the biological half-life, and thereby its activity and accumulation in different tissues of the body.

Absorption into the body

Due to the small molecular size of essential oils, they can penetrate through the dermal route (external skin), ingested or inhaled (entry into the lung cells), and their toxins enter the blood stream easily, as if injected. This is why dermal medicine patches, inhalers, sublingual and medications dispensed via breathing treatments is so effective.
• Damage caused by absorption through the skin depends on the concentration of the essential oil, how quickly it is absorbed, the area covered, how long it was left on the skin and what other products where used.
• The effect of vaporizers, diffusers and simply breathing in fragrances can cause damage to the lungs due to the chemicals in essential oils. The direct entry of lipophilic components from essential oils via the olfactory mucosa is quite substantial and can act very quickly, especially in babies and young children. Olfactory pathways provide a direct route to the brain. In one study, 1,8-cinoel was rapidly absorbed from eucalyptus essential oil, with plasma concentrations at their peak after 18 minutes.

The National Institute of Occupational Safety and Health has recognized 884 poisonous substances used in the fragrance industry. Many are synthetics from petrochemicals. They cause cancer, birth defects, central nervous system disorders, allergic respiratory reactions, skin and eye irritation. Only one-third of the materials used in fragrances have been tested for safety. Testing is limited to individual materials and not the synergistic or modifying effects of materials in combinations. Fragrance materials are absorbed into the body via the respiratory system and once absorbed cause systemic effects.

In a 1997 clinical review of the adverse reactions to fragrances, it revealed that 6 million people experienced an allergic reaction to fragrances. Many of these people reported a major impact on their quality of life, including migraine headaches, dizziness, nausea, fatigue, breathing difficulties, difficulty concentrating. Fragrances are known to modify cerebral blood flow and several common fragrance materials are known to have potent sedative effects when inhaled. They act on the same receptors in the brain as alcohol and tobacco, altering mood and function. It goes without saying that fragrances are recognized as triggers for asthma. Respiratory irritants are known to make airways more susceptible to injury and allergens, as well as allergies, sinus problems and other respiratory disorders.

Drastic reduction in exposures to irritants is essential.

It is difficult for people who are sensitive to fragrances to obtain fragrance-free products and suffer health effects as a result of using scented products. Products that are labeled ‘unsented’ or ‘hypoallergenic actually contain fragrance materials and are particularly problematic. Not only perfumes and colognes, but air fresheners, strong soaps, scened candles, potpourri, toilet bowel deodorizer, Fabreeze, Lysol spray, laundry soap and fabric softener on people's clothes, incense, and diffusers drive sensitive people out of the room or building. I have asked myself, "How long can I hold my breath while using a public restroom?" I would rather smell the odor that's being covered up than the chemicals in the product being released into the air.


Most essential oils have GRAS (generally recognized as safe) status granted by the Flavor and Extract Manufacturers Association and approved by the US Food and Drug Administration (FDA) for use in food and many appear on the Food Chemical Codex.
• Critical to GRAS assessment are data of metabolic fate and chronic studies rather than acute toxicity. The same chemicals are used in foods, household cleaners, air fresheners, personal care products, perfumes and cosmetics, so there is a greater risk of impact due to accumulated oral, inhalation and dermal absorption.
• As so many products contain essential oils and components, it is not surprising that fragrance materials have been found to interact with food flavorings, which is of increasing concern. Example: Musk xylene is one of the most common fragrance materials and it is found in the blood samples of the general population and bound to human hemoglobin. There have been very few published reports on the neurotoxic effects of aroma chemicals, such as musk ambrette, but dermal tests revealed its neurotoxic properties when absorbed through the skin. Repeated application of synthetic musk (versatile) is also neurotoxic. Continued application caused internal organs to turn bluish, and irreversible myelin sheath damage occurred, similar to multiple sclerosis.
• Unfortunately, the industry does not test for the neurological and respiratory effects of fragrance materials.
• Studies have shown an abortifacient effect during pregnancy, no fetal toxicity but significant maternal toxicity and a teratogenic (abnormalities in physiological development) affect from aromatherapy, as well as reproductive organ and hormone effects. Studies showed several xenoendocrine disruptors in vitro resulting in smaller male reproductive organs and enlargement of the prostate gland in adult males, as well as oestrogenic effects. Essential oils can cross the placenta and their effects can be compounded in utero. Pregnant women, women who are breastfeeding and babies should avoid essential oils. This includes aromatherapy. This is especially true of the following oils: Rosemary, Lavender, Sage, Mugwort, Tarragon and Wintergreen. Babies and toddlers cannot fully metabolize them. Some oils can cause adverse reactions in older children, especially those who have hyper-reactive airways. Excessive intake can cause liver damage, especially in children.
• Several fragrance materials are carcinogenic while others are possible carcinogens.
• The use of several essential oils and components have been forbidden by the Research Institute for Fragrance Materials and others have concentration limits imposed, so it makes no sense why they would be approved for use in food. This exposes the use of essential oils by the average consumer as a very risky practice.


The adverse effects of essential oils is multiplied by exposure to UV light. These include yarrow, angelica, neroli, petitgrain, cedar wood, rosemary, cassia, calamus, cade, eucalyptus, orange, anise, bay, bitter almond, ylang yang, cumin, rue, dill, sandalwood, lemon, lime, opoponax, verbena, carrot seed and linaloe. Many of these photosensitizes are now banned or restricted. The most common fragrance components causing allergy are cinnamic alcohol, hydroxycitronellal, musk ambrette, musk versatile, musk xylene, isoeugenol, geraniol, benzyl salicylic, sandalwood oil, anisyl alcohol, benzyl alcohol and coumarin. Children were found to be sensitive to Peru balsam, due to the use of baby care products containing talcum powder.

Increasing problems

With the increased popularity of essential oils, problems with their use has also been increasing. For example, dermatitis caused by tea tree oil has been reported, which was previously considered to be safe. Tea Tree oil is an antiseptic and anti-fungal. It may be effective when used to treat athlete’s feet or fungal nail infections, but tea tree oil is dangerous if consumed. It causes diarrhea, nausea, severe rash, confusion, stomach pain and coma. Never use tea tree oil with lavender oil topically. People with skin conditions such as eczema experience blistering skin.
• Respiratory problems and adverse skin reactions worsen with prolonged fragrance exposure.
• Prolonged exposure to essential oils affects heart rate and may be harmful to cardiovascular health.
• Several fragrance chemicals affect the immune response of the skin when inhaled, but the systematic and long-term effects of most fragrance materials are not known.
• Most chemical data sheets and Material Safety Data Sheet (MSDS) information on fragrance materials clearly state “the chemical, physical and toxicological properties have NOT been thoroughly investigated.”
• Many materials that were widely used for decades in the past had severe neurotoxic properties and accumulated in body tissues. All essential oils are cytotoxic (toxic to cells) for human lymphocytes.

People are cautioned not to use powerful substances if they have any preexisting health conditions. I have yet to meet someone these days who doesn’t have a ‘preexisting health condition’, and many are undiagnosed.

Different perspective

Instead of repeatedly self medicating a chronic symptom with essential oils, I feel the best course of action is to find out what is causing the symptoms, like headaches, and resolve the problem where it is, not where it isn’t. The fact that the same symptoms keep surfacing in a perpetual cycle indicates that the cause has not been addressed and resolved. If it had been, the language of the body would stop communicating a problem via symptom, because the problem would be gone.

  • Scientific studies back up claims that essential oils do have powerful therapeutic properties. Anything powerful enough to have a beneficial effect on the body could also have a negative effect that is just as powerful. Power deserves respect and requires wisdom.
  • What works for one person may not work for a thousand other people and many more will experience medication interactions while others will have side effects.
  • Essential oils may have beneficial applications, but when they interact with medications or are misused, they can become toxic to the user and dangerous. The benefits of an essential oil can be obtained by using the fresh or dried herb in a potpourri, sachet, tea or tincture. Homeopathy is also another, possibly safer, alternative.


It is critically important that you know what you are exposing your body to; food, supplements, beverages, personal care products, environmental toxins, medications, etc.

The use of essential oils in any form will counteract any healing strategy we do with respect to the Candida Exit Strategy protocol.

If you have questions, email to schedule your free introductory consultation. I look forward to serving you. JVW