Oil Diffusers Make Your House Smell Great, But Are They Safe?

As Lee noted, there is potential for a diffusing device to malfunction or burn the user through incorrect handling, so many people choose to avoid styles that involve use of an open flame for safety reasons. Not surprisingly, these tend to be the least expensive type of diffuser.

Still, that doesn't mean the other types are perfectly safe. Although Lee doesn't tell patients which type of diffuser to use at home, he is leery of ultrasonic diffusers that employ a water reservoir to function. "Like other water-containing home machines (like a CPAP), they can be difficult to clean and encourage growth of microbes," he explains.

And Lee would never recommend using essential oils in a health care setting. "In 2016, patients' families in an ICU in Austria shared a bottle of essential oil, resulting in the spread of a multidrug resistant strain of bacteria," he recalls. Fortunately, the outbreak was handled appropriately, and infection peaked at seven people.

Diffusers can also be a risky proposition for people who are sensitive to smells or who have respiratory issues. "In some hospitals where aromatherapy has been permitted, whole-room diffusers have been associated with sensitivity reactions – staff and other patients have been affected," Lee explains. "In health care spaces, there are lots of different patients – and some may be suffering from respiratory conditions worsened by essential oils."

Another side risk of essential oil use is that although the oils might not cause any actual harm, their use could cause delay of evidence-based treatment, as some people wait to see if the oils alleviate the illness in question. So, a simple case of croup that could have been handled via a regular doctor's visit suddenly morphs into an ambulance ride to the nearest emergency room, as a New York Times article pointed out.

It's not that surprising that people would delay treatment because so many essential oils have been touted to relieve a host of symptoms of many debilitating ailments, like depression, anxiety, nausea and insomnia. Studies have shown that some varieties of oils are effective antimicrobials, and oils from plants like garlic and thyme can even take down the Lyme disease bacterium better than the standard antibiotic. But human trials have yet to confirm that last claim.

The lack of large-scale research is indeed a sticking point for many doctors. "For clinicians to be comfortable prescribing and treating patients with essential oils, rigorous research needs to be performed to evaluate each health claim," Lee says, noting that almost all studies on essential oils to date measure a short-term effect such as perceived anxiety before and after a doctor's visit. "Ideally, each essential oil would be researched in the context of each health claim it is purported to have. For example, if lemon oil is supposed to make your skin shinier and also increase your mood, then research would have to be designed for each of these."

Currently, essential oils are not subjected to the same rigorous standards as medical drugs because they're classified as botanical products. "As such, they are not regulated as a pharmaceutical, and do not need to have laboratory testing verifying their contents or concentrations," Lee says. "This has led to essential oil producers providing their own false 'certifications' on their label," such as ultra-pure, authentic and distilled. Don't fall for the labelling hype, though. "None have meaning," he says.

"Practically, I feel that patients should be able to pursue whatever means they desire for wellness. Life is hard! If you feel that sniffing a lilac makes it less hard, then you should go for it," Lee says. "I just want patients to have the big picture in mind: Essential oils are NOT proven by science, they may have side effects we don't know about, and you should tell [your physician] about everything you are taking."

With those precautions in mind, if you still want to use an oil diffuser, what should you do? Jamie Bacharach, a licensed holistic doctor and head of practice at Acupuncture Jerusalem, has extensive experience with advising patients on oil diffusers. She recommends the following when deciding what oils to use in your diffuser: