Are Your COPD Patients Using Eucalyptus Oil? Know the Risks

Medscape

20-05-2025

There's been renewed interest in recent years for concentrated essential oils to replace or complement pharmaceutical treatments. This is especially concerning among patients with chronic obstructive pulmonary disease (COPD), who might be eager to turn to alternatives but are unaware that COPD increases sensitivity to lung irritants like essential oils.
Eucalyptus oil might be at or near the top of the essential oils list for these patients, given its storied history in both ancient and modern medicine for treating colds and respiratory illnesses. Its inclusion in the United States and European pharmacopoeias has also reinforced its legitimacy. And, today, patients are at risk of confusing the primary active ingredient in eucalyptus — the monoterpene 1,8-cineole (eucalyptol, which has been shown to reduce COPD exacerbations when used adjunctively) — with concentrated essential oils that can be purchased online and in stores here in the United States.
Ni-Chen Liang, MD
'The more potent active ingredient, eucalyptol (in capsule form), is approved in Germany — not the essential oil of eucalyptus, which contains other compounds. I recommend against using any sort of inhaled essential oils for patients with chronic respiratory illnesses, mainly because they are unregulated and unstandardized,' explained Ni-Chen Liang, MD, an integrative pulmonologist affiliated with Scripps Memorial Hospital Encinitas in Encinitas, California.
'The substances that come out when you create eucalyptus oil are a 'gamash' of all sorts of chemicals — some benign, some which taste good, and some that may be irritating or even dangerous,' said Neil Schachter, MD, pulmonologist and professor of medicine (pulmonary, critical care, and sleep medicine) at the Icahn School of Medicine at Mount Sinai, New York City.
'They can also produce volatile organic compounds (VOCs) related to their formulas, which contain fillers and other constituents,' Liang said.
Hidden Dangers
Eucalyptus oil was first used by Aboriginal Australians, who crushed the leaves for their antiseptic properties or steamed them for their expectorant activity. Today, eucalyptus oil can be found in mouthwash and soap, used topically to relieve pain or repel insects, or added to cleaning products due to its disinfectant properties.
However, inhalation via diffusers or directly from the bottle can trigger different respiratory reactions, including cough, wheezing, shortness of breath, as well as respiratory distress.
'The vapors contain oil, ie, fatty products that can be irritating in and of themselves,' said Schachter. 'There are cases where people have inhaled these oils and developed lipid pneumonia, which is very hard to treat,' he said.
Juan Rojas, MD
Anything inhaled into the lungs is a risk, said Juan Rojas, MD, assistant professor, Department of Internal Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine at Rush University Medical Center in Chicago. Rojas compared inhaling essential oils to e-cigarettes, which, in addition to tobacco, contain a variety of chemicals and additives that cause a lung reaction in the short term and create inflammatory patterns in the medium and long term.
'Another problem is that when ingested, eucalyptus oil can be distressing to the gastrointestinal tract. In larger doses, it can actually have some neurological impact as well, including seizures,' said Kalilah L. Gates, MD, associate professor of medicine (pulmonary and critical care) and assistant dean of medical education at Northwestern Feinberg School of Medicine in Chicago.
Clinical trial data have also shown a significant association between long-term exposure to essential oils and cardiopulmonary effects such as increased heart rate and blood pressure and a decline in percentage predicted peak expiratory flow rate in healthy volunteers. In the study of 200 participants (who were homemakers), long-term exposure referred to daily hours (> 4/d) and the study period, which was 10 years.
About Eucalyptol
Eucalyptol is rapidly absorbed and quickly distributed throughout the bloodstream, which allows it to reach the bronchial system, where it is expelled by the lungs. It's been shown in various preclinical studies to have anti-inflammatory, antioxidant, mucolytic, and bronchodilatory activity, as well as antimicrobial effects.
For the past decade, enteric-coated eucalyptol capsules containing 100 mg or 200 mg of 1,8-cineole have been available in Germany for adjunctive treatment of inflammatory respiratory disorders, including asthma and COPD. Due to its limited bioactivity, frequent administration is required.
Clinical evidence of eucalyptol's effectiveness is somewhat limited. Findings from a 2009 double-blind, placebo-controlled, multicenter study also demonstrated that when used along with beta-agonists, anticholinergics, corticosteroids, or combinations in patients with stable COPD, severity and duration of exacerbations over 6 months were significantly decreased compared with placebo.
However, Liang was quick to point out that studies of oral eucalyptol preparations in pulmonary patients have not been robust enough.
'I haven't been able to find anything written by a multitude of different authors, which, to me, is a red flag. We want naturally occurring substances to be well tested in multicenter studies across a variety of different patient populations outside of Germany to ensure that results are reproducible,' she said.
Rojas concurred. 'Even with the data in Europe, I would say that the studies have been underpowered to support large-scale adoption or suggest that the active ingredient for patients with moderate or severe COPD could be considered an adjunctive therapy with traditional medications,' he said.
'It would be difficult for me to make a recommendation without knowing the full impact,' said Rojas.
Open Dialogue
Like many chronic diseases, it's important to meet patients where they are, including their use of unapproved or unwise treatment strategies.
'More times than not, they've already figured out their triggers for worsening respiratory symptoms, what does and doesn't work for them, and what predicts a good vs a bad day from a respiratory standpoint,' said Liang.
'There's a lot of popularity and claims related to essential oil use, and ultimately, we need to partner to find healing modalities (which may or may not include essential oils) that are ultimately helpful and minimize harm,' she said.
Kalilah L. Gates, MD
Gates suggested that when it comes to eucalyptus essential oil vs eucalyptol, education of both patients and doctors is key.
'The issue is that we had a study showing that a particular component — the active ingredient of eucalyptus oil was isolated and put into the capsule form and showed benefit. And then we extrapolated and said, 'well, let's just take (or inhale) eucalyptus oil. It's not the same thing,' she said.
'I feel that it's my responsibility to make sure that patients have the information they need to make informed decisions. It's about being willing to communicate and have open conversations about what they may be taking in addition to medications that I prescribe,' said Gates.
Liang, Schachter, Rojas, and Gates reported no relevant financial relationships.