March 30, 2017
Ripe tangerines with leaves and bottle of essential citrus oil

Essential Oils: What You Should Know

by Amanda Z. Naprawa  |  

Complementary and alternative medicine is a rapidly growing business in the United States. Many people seek out non-traditional therapies, from acupuncture to yoga, to help alleviate a host of conditions. And many practitioners of traditional medicine now incorporate alternative therapies into standard practice.

One popular alternative practice is the use of essential oils—fragrant oils made from plant or flower extracts that are applied to the skin, inhaled, or both to achieve a therapeutic benefit. This is also known as “aromatherapy.” Since essential oils come from plants, they are generally marketed as safe alternatives or add-ons to conventional treatments. But do they work? And are they really safe for everyone, including children? Here’s a practical overview of essential oils, the evidence on them, and their potential risks.

How essential oils are used

Aromatherapy is generally defined as the therapeutic use of essential oils from plants for the improvement of physical, emotional, or spiritual well-being. That could entail inhaling them, absorbing them through the skin, or a combination (for example, massage using essential oils). Less commonly, oils are ingested orally, such as through a glass of tea or spoonful of honey.

Companies that sell essential oils oftenascribe specific therapeutic benefits to specific oils. For instance, lavender oil is marketed as a stress reliever and sleep agent. Tree tea oil is promoted for antiseptic and anti-inflammatory uses. Oil of peppermint is often sold as a digestive aid. And you can find anecdotal stories all over the Internet and social media touting different oils for different purposes.

Do essential oils work?

It's hard to answer that question because there simply are not very many high-quality scientific studies on the therapeutic use of essential oils. One challenge in studying essential oils is that they are not standardized—that is, because the oils are extracted from plants, their composition is dependent upon weather conditions, seasons, even the time of day they were harvested. This means that unlike synthetic drugs, which are reproduced under identical conditions, oils often vary from bottle to bottle. It’s hard to do a scientific study when the compound being studied isn't always the same.

Another problem with studying essential oils is that it can be difficult to determine whether it was the oil or another aspect of the treatment that produced relief. For example, oils are sometimes applied via massage, which may have its own therapeutic benefits. So if a person reports, say, reduced back pain after a massage with a certain oil, it is difficult to determine whether it was the massage, the oil, or the combination that made the difference.

Some of the most promising research on essential oils has been in agriculture, where they’re emerging as a potential alternative to the prophylactic antibiotics often given to farm animals to prevent infection. In a study published in Poultry Science, for instance, researchers found that chickens that ate food with a standardized dose of oregano oil were 59 percent less likely to die from a common poultry disease called ascites syndrome. An earlier study in the same journal showed that adding a blend of essential oils to the drinking water of farmed chickens limited cross-contamination with salmonella when those chickens were processed for food.

Some preliminary evidence suggests that certain oils may also help fight bacterial infections in humans. In an older study in the Journal of Hospital Infection,tea tree oil (melaleuca alternifolia) appeared to be effective in eliminating methecillin-resistant Staphylococcus aureus (MRSA) on the skin of hospital patients. And a Polish study in the journal Molecules showed that oil of basil and oil of rosemary inhibited the growth of some strains of drug-resistant Escherichia coli (E.coli), a bacteria which can cause severe gastrointestinal illness. But the study was conducted in a laboratory; the benefits have not been tested in humans.

Interestingly, one of the more useful—and least controversial—applications of essential oils may be as a replacement for antibacterial soaps and household cleaners (which we recommend against using because of their link to antibiotic resistance).

Risks of essential oils

As we’ve reported previously, just because something is "natural" doesn’t necessarily mean it is safe. And even if an oil is safe when applied topically, it could be dangerous if ingested, particularly by children. One example is oil of wintergreen, a popular ingredient in over-the-counter oils and lotions intended to alleviate musculoskeletal pain. Oil of wintergreen is in fact 98 percent methyl salicylate, essentially the same as the active ingredient in aspirin. One teaspoon of the oil is the equivalent of about 22 adult aspirin tablets, and ingesting as little as 4 milliliters (slightly less than a teaspoon) of the oil can be fatal in children. And while tea tree oil is generally considered safe to apply topically (though some people may find it irritates their skin), accidentally swallowing even a small amount orally has been reported to cause loss of muscle coordination and unresponsiveness.

The same goes for swallowing camphor and eucalyptus oils, which even in small doses can cause seizures, vomiting, and potentially be life-threatening.

Another thing to keep in mind when using essential oils for yourself or your children is that aromatherapy products are unregulated and unlicensed. This means that there is no oversight for the manufacture or use of these products. Like dietary supplements—which also don't have to be proved safe or effective before they're sold to the public—essential oil products are required to carry a disclaimer that the FDA has not evaluated the product and that it is not intended to diagnose, treat, cure, or prevent disease.

It’s especially dangerous to use essential oils in place of regular medicine, which, believe it or not, some websites eagerly encourage, even for illnesses as serious as asthma. In fact, certain aromas and scented oils can actually trigger asthma attacks. So if you experiment with essential oils at all, do it as a complement to, not a replacement for, any formal treatments you are using unless you and your provider decide otherwise.

Bottom line: Essential oils may have some therapeutic benefits but should not take the place of conventional, evidence-based medications and treatments, and they should never be ingested. If you are interested in using these oils, talk to your healthcare provider about them, and watch for any skin irritations or other problems that may arise after use. Also note that essential oils, like perfumes, release volatile organic compounds, small particles that can cause eye and lung irritation; people with asthma in particular should probably avoid them. Keep any essential oils well out of reach of children and pets.