Back in 2014, I conducted a series of experiments inhaling essential oils through my nebulizer. I began these experiments at a time when I was due to use oral antibiotics again (a regular occurrence for me as a result of my chronic cystic fibrosis lung infections) but a snow storm prevented me from getting to the pharmacy. As they say, necessity if the mother of invention (or in this case, discovery)!
Why Use Essential Oils?
In 2014, I was in the midst of my clinical herbal training and had been learning about various medicinal plant constituents. In particular, the constituents called essential oils often have potent antimicrobial (antibacterial, antifungal, & antiviral) power. So I decided it was time to try an experiment with them to see if they could help me control my lung infections. I was very happy with the results and I'd love to share my findings with you!
Volatile essential oils from plants have been used for hundreds of years in traditional medicine to treat infections, reduce muscle and gut spasms, and calm the nervous system. But in recent years, the scientific interest in essential oils has grown as antibiotic-resistant superbugs (like the MRSA that I had in my lungs for two decades) are proving themselves to be beyond the control of the conventional pharmaceutical approach. Essential oils can be very effective against antibiotic-resistant bacteria, and there have been many in vitro studies testifying to this effect.
I got in touch with several other CFers who had experimented with essential oils and had great results. This further encouraged me to give it a try. Until I started using the medication Trikafta in 2019, I had been reliant on regular courses of antibiotics every two weeks to control my lung infections. Knowing the negative effects of antibiotics on my body (i.e. disruption of gut flora, antibiotic resistance, weird side effects, etc.) I continually sought alternatives but used them when I had to.
In this article, I will first discuss my experiments and their results. Secondly, I will present the scientific research on how essential oils work as well as the physiological actions and characteristics of the oils that I've used in my experiments.
My First Experiment
First, I began inhaling Eucalyptus radiata oil twice a day. I would put 2 mL of hypertonic (7%) saline (essentially half of a plastic 4 mL vial) in my Pari nebulizer cup and put in two drops of eucalyptus oil. I'd shake it a little to break up the big globs of oil that float on top, then start the nebulizer. It takes about 5-10 minutes to nebulize. I nebulized the eucalyptus at the end of my morning and evening treatments at the time when you would usually inhale an antibiotic like Tobi or Cayston.
At first, the eucalyptus was a little irritating and it made me cough up a good amount of mucus that was in my lungs. Over the next week or so, I developed a tolerance to it so that the irritated coughing subsided. The irritating cough was really not so bad because it made my cough more productive, and the menthol-like feeling of the eucalyptus soothed my throat and ultimately reduced my spasms. Part of my irritation might have also come from the hypertonic saline, which also makes me cough. In my later experiments I used normal (0.9%) saline. Anything I use to dilute the essential oils in my nebulizer is always sterile (processed to be free of pathogens), whether that be sterile saline or sterile water.
After my course of oral antibiotics ended I had been having my usual spasmy morning cough (an annoying asthmatic-like hacking for 20-30 minutes), chest tightness, shortness of breath, tons of yellow mucus, and a feeling of chronic inflammation and irritation in the lungs. I had also been getting night sweats and would often wake up at 3 am to cough with a scary feeling like I had woken up from sleep apnea. My energy throughout the day was lower than when on antibiotics. My ever-present low-grade fever required one acetaminophen or ibuprofin every morning at 9 am.
After only two treatments of inhaled eucalyptus I immediately felt an effect. The eucalyptus stopped my spasmy cough that first day and stayed away as long as I nebulized eucalyptus. EO is bronchodilating, a counter-irritant, antispasmodic, and anti-inflammatory, so it almost immediately made my lungs felt more open, less inflamed, and more resilient. After only a few days I was able to take in deep breaths and I could feel air moving all the way down to the lower parts of my lungs, something that I can rarely do except when on vancomycin. My shortness of breath was gone. My cough was less spasmodic but more productive, as if each cough was more efficient at getting mucus up. After a week I noticed a small decrease in the amount of mucus I was coughing up, and that amount decreased still in the following weeks. The oil seemed to be getting more effective with time. My night sweats left. I could sleep through the night again without waking up from sleep apnea to then hack up mucus. My lungs felt open and clear throughout the night and even when waking up. My morning cough was minimal enough that I could eat a small breakfast before starting my morning treatments, something not usually possible when off antibiotics (I usually coughed too much to get food into my mouth). I still had my daily low-grade fevers, which is an indication that the infection had not been completely controlled. I still had to treat the fever with a morning acetaminophen, but my energy had improved. My sinuses cleared up after about 2 weeks, and the only stuff that comes out is clear snot, no more green plugs. The coating on my tongue (an important diagnostic tool in traditional medicine) had shifted from my usual coating of thick white-yellow-brown gunk to a thin white coat.
Needless to say, I was really excited about all this. Eucalyptus had improved my breathing significantly with no impact on my gut flora and no other side effects. But the real test was the results of my FEV1. After 3 weeks of eucalyptus oil my FEV1 was up 8% from 2 months before! It was now at the same level that it was after my last 10 day course on IV vancomycin in December! I had even caught a cold the week before my test (kicked it in a record-breaking 3 days!) and still my numbers were high. During the cold, I also added a drop of eucalyptus to my sinus rinse bottle, which helped reduce mucus build up and inflammation. However, because I still had low-grade fevers and mucus production, I will not claim that eucalyptus was a "cure" or a permanent solution. About a month later I did have to go on oral antibiotics, but eucalyptus essential oil was a complementary treatment with benefits antibiotics couldn't offer. While eucalyptus is an excellent bronchodilator (opening airways), expectorant, and anti-inflammatory, it is not as antimicrobial as many other essential oils.
Eucalyptus worked so well that I thought I would experiment with other oils. After 4 weeks of nebulizing eucalyptus, I decided to stop it and try pine oil (Pinus sylvestris, a.k.a Scotch Pine) alone. I decided to try it alone to isolate the variables and be more "scientific" about it. After five days of only pine oil it became clear that it was nowhere near as effective as eucalyptus. I began to notice an increase in my mucus load and my lungs became a bit more irritated in the mornings. The spasmy cough still did not return, but I felt my lung capacity begin to decline very slowly and my shortness of breath/ diaphragm tightness returned. After five days of this trend I decided the experiment was over (I planned to do a two-week trial but the results were clear enough after 5 days).
For the next three days I mixed 2-3 drops of pine with 1 drop of eucalyptus in 2 mL hypersal and nebulized this twice a day. My symptoms improved somewhat. My shortness of breath went away and my diaphragm relaxed again. My morning coughs became less irritated.
For the next two days I added cinnamon leaf oil to the eucalyptus (1 drop to 1 drop) and also tried cinnamon leaf by itself. It was really intense! I wanted to try cinnamon because the scientific literature has shown that cinnamon oil, with its high levels of cinnamaldehyde, is one of the strongest antibacterial essential oils out there . It may be strongly bactericidal, but it burned my throat and numbed my mouth. It was so irritating that I think it actually worsened my shortness of breath. After a few days of that, I decided the pain wasn't worth it, and so I move on to the next oil.
After these two unsuccessful experiments, I came up with a combo that I think was pretty effective. In the morning I nebulized 1 drop of eucalyptus, 1 drop tea tree oil (TT), and 1 drop lemongrass mixed in normal sterile saline. I had a box of normal saline syringes left over from my home-IV treatments in December, so I decided it would be less irritating to use than hypertonic 7% saline as my dilution liquid. I nebulized the eucalyptus and TT together in 2 mL saline, then the lemongrass (LG) by itself in 2-3 mL saline. I nebbed the LG by itself because it is pretty irritating (similar to cinnamon, spicy, but a little milder, and does not cause me shortness of breath) and I have to inhale it with my mouth open and unsealed around the neb cup or else my throat will burn. I don't want to waste any TT or eucalyptus, so I neb the LG separately this way. I recently began to use LG in combo with 1 drop of pine oil (a much more mild oil), which seems to reduce the irritating effects of LG a little bit so that I can inhale it without my throat burning as much. Then, at the end of this treatment, I would add in another 1/2 mL of saline and neb that to make sure I get every last morsel of essential oil left in the neb cup. I don't want to waste any of it since it's both precious and expensive. I put up with the irritation of the LG because I feel that it is effective. In the two weeks of its use my mucus production had declined to be even less than what it was in my first experiment with just eucalyptus. In the scientific literature, LG has been shown to be particularly effective against MRSA (which I will discuss later). In the evening I nebulized 1 drop eucalyptus, 1 drop TT, and 1 drop pine oil together in 3 mL saline. This seems to be a soothing combo that lets me sleep better through the night, versus when I nebbed LG before bed it occasionally caused me a bit of irritation which woke me up with a dry cough at 3 am.
There have been numerous in vitro studies on the antimicrobial effects of essential oils on bacteria, viruses, and fungi in the last decade or so. Interestingly, because the pharmaceutical-industrial complex dominates modern medicine in the US and Europe to the point where almost all research is done for the development of multi-billion dollar blockbuster drugs, some of the most innovative and groundbreaking research on the use of herbs and non-patentable natural medicines is coming out of Asia, the Middle East, and Eastern Europe. There are a handful of studies coming out of research universities in the US, Australia, and Europe as well. I find it fascinating that countries that are more frugal and less obsessed with capitalist ideology are finding cheap, safe, and innovative ways to make people healthier, often times by rediscovering natural medicine. Many of these countries also have thriving traditional and folk healing modalities that modernity has not yet been able to suppress, thank goodness.
Essential oils may be a useful tool as we move into an era dominated by antibiotic-resistant superbug infections. Essential oils do not run the risk of having bacteria develop resistance to them because essential oils are complex cocktails of many chemical constituents (sometimes over 100) working synergistically to kill microbes and pests. Plants evolved to produce essential oils to protect themselves from microbes and pests, and also to attract beneficial pollinators and communicate with their neighbors. When experiments isolate single constituents from essential oils (like 1,8 cineole from the whole eucalyptus oil) and apply these to bacteria, single constituents generally have weaker activity against bacteria than the whole oil or than multiple oils applied together in a formula. This is because whole oils contain many different constituents that are antimicrobial, immunomodulating, antioxidant, antispasmodic, bronchodilating, analgesic (pain reducing), anti-inflammatory, and so on, all working synergistically . In addition to essential oils' direct inhibitory effects against microbes, they also commonly contain constituents that stimulate the immune system to mount a more effective immune response to invading pathogens. Thus only focusing on essential oils' antimicrobial powers succumbs to modern mechanical medicine's over-emphasis on killing pathogens, neglecting their other valuable applications. In traditional herbalism we understand that modern medicine's bias towards reductionism is not effect in our clinical experience.
Using whole essential oils, with their varying combinations of different constituents, will help prevent bacterial resistance to these oils. The chemicals produced by plants high in essential oils constantly shift depending on weather, the season, the climate, soil composition, pest predation, and many other environmental factors. Even oils from two plants of the same species living side by side may have slightly different chemical profiles. Or the essential oils produced in the spring may differ from those produced from the same plant in autumn . Remember, plants are unique individuals who change as they grow, just like you and me! This can make it difficult to "standardize" the chemical composition of an essential oil for therapeutic use, but I like to think of this in a positive way - it further reduces the risk of bacterial resistance if we're constantly changing the rules of the game on them. The main reason why bacteria so easily develop resistance to pharmaceutical antibiotics is that antibiotics consist of only one chemical constituent, and when a bacteria figures out a way around it, the antibiotic less useful. This is called antibiotic resistance. Some antibiotics are used in combination, like the common anti-Pseudomonas combo of IV tobramycin and ceftazidime for cystic fibrosis lung infections, or oral Bactrim (a combo of sulfamethoxazole and trimethoprim), or the standard combination of rifampicin and fusidic acid.
Furthermore, it's been found in preliminary research (and through several CFers personal experiences) that using formulas made of a mixture of different essential oils are even more effective at smaller doses compared to single oils . Studies have shown that certain plant constituents, when used together make each other more effective at killing bacteria, such as 1,8-cineole and terpenine in tea tree oil. We call this synergism. A study by Weber University and Young Living found that blended oil formulas were more effective than any of their single oils alone, and even more effective than the strongest of the single oils (i.e. lemongrass). It's been found that essential oils and their constituents can work synergistically with antibiotics as well .
All plants have different chemical constituents and different energetic signatures which make their oils more or less effective for certain microorganisms and human constiutions. All oils are at least somewhat antimicrobial because they are made of lipophilic organic compounds and many microorganisms (especially gram-positive bacteria, viruses, and fungi) have cell membranes that are made up of a lipid bilayer. Lipid or lipos comes from Greek meaning fat. Lipophilic means "fat loving", so when cells have a lipid bilayer it means fats bind to and pass through then. Our skin, for example, is made up of these kinds of cells, and it's one reason why human skin can absorb oils. As very small oil-loving constituents, essential oils can bind to the cell membranes of microbes and disrupt the lipid envelope that protects them, essentially ripping a hole in them. When essential oil constituents get inside microbial cells they can do damage to the organelles or DNA on the inside. Gram-positive bacteria (i.e. MRSA, all Staphyloccocus, mycobacteria, etc.), enveloped viruses, and fungi are especially vulnerable to essential oils because they are protected on the outside by a lipid bilayer. Gram-negative bacteria (i.e. Pseudomonas) have lipophobic (fat-fearing)/hydrophilic (water-loving) cell membranes that are covered in a barrier of polysaccharide chains. This means that volatile oils and fat-soluble chemical constituents have a harder time killing gram-negative bacteria . So while studies have shown that essential oils are very effective against gram-positive, viral, and mold/yeast infections, they are less effective against the CF's arch-nemesis, Pseudomonas aruginosa. However, it doesn't mean they're completely ineffective. Tea tree oil has been shown to be mildly effective against multi-drug-resistant Pseudomonas .
Although all essential oils are somewhat bactericidal, some are much more powerful than others. This has a lot to do with their chemical constituents. Certain classes of essential oil chemical constituents, such as aldehydes and phenols, are more antimicrobial than other chemicals such as alcohols, ketones, or ethers . In addition, essential oils' direct antimicrobial actions are not their only strengths, so we should not be myopic when it comes to choosing oils based on their bactericidal capacities only. Many oils have other actions as well, such as anti-inflammatory, antispasmodic, mucolytic (thins mucus), nervine (calms the nervous system), bronchodilating, immunomodulating, and so on. For example, eucalyptus is not the most bactericidal oil on the block, but it is excellent at helping respiratory function in other ways, as I will describe below. I would always make sure to include at least a little eucalyptus in my formula for all of its benefits, not just because it kills bacteria.
Eucalyptus is a genus of trees which includes over 500 species native to Australia, Tasmania, and nearby islands . A handful of these species have been extensively studied for their medicinal applications, especially Eucalyptus globulus, or the Blue Gum tree. The major constituent in most eucalyptus species' oils is 1,8-cineole, also called eucalyptol. There has been a lot of scientific study on this constituent, especially concerning its effect on the respiratory and immune systems. Eucalyptus oil has been found to increase phagocytosis by the white blood cells of the innate immune system without increasing cytokine production. In other words, eucalyptus stimulates a better immune response without increasing inflammation in the airways. In fact, in-vitro studies have shown that eucalyptus reduces cytokine production in already-irritated cells, which would explain why it helped me so much when I felt inflamed. It is thought that 1,8-cineole is the main reason for the ability for eucalyptus to reduce inflammation. In fact, one study on asthmatics found that 1,8-cineole reduced inflammation and allergic response so much that they were able to reduce their dose of prednisone, even after treatment with 1,8-cineole had stopped. It is also thought that this constituent can control airway mucus hypersecretion, reducing respiratory exacerbations in asthma, sinusitis, and COPD . Eucalyptus might also create this effect in CF. Human and animal studies have shown that 1,8-cineole significantly reduces symptoms of chronic bronchitis, sinusitis, and COPD.
Although 1,8-cineole is great and there has been a lot of research on it, it may not be as effective against microbes as the whole essential oil. One study showed that although 1,8-cineole is a major component of many eucalyptus species oils, its strongest antibacterial constituent may be alpha-terpineol, which is found in smaller quantities in the oils . To me, this is further proof that we should not succumb to conventional reductionistic thinking in the use of essential oils or herbs in general. Whole plants containing synergistic cocktails of constituents are often more powerful than isolated chemicals, even if those isolates can be delivered at higher doses.
Out of 18 essential oils tested against Candida albicans, E. globulus was the most effective followed by peppermint, ginger grass, and clove. E. globulus was found to be more effective than fluconazole (a commonly used anti-fungal drug for yeast infections), and peppermint oil was found to be as effective as fluconazole . One study found E. globulus to be not as effective against Staph as tea tree oil, but it is the most effective thing out of anything (including pharmaceutical drugs and synthetic chemicals) against dental cavities and plaque, and that is why many toothpastes now include eucalyptus as an ingredient. Eucalyptus may also be effective against MRSA, depending on the species. In one study on essential oils' effect against MRSA, E. citriodora was found to have the largest zone of inhibition (i.e. the radius of bacteria death upon exposure to the oil) of the eucalyptus species (50 mm) with E. radiata second (25 mm). E. globulus was ineffective. E. citriodora was only moderately effective when compared to the most effective oils in this study: lemongrass (zone of inhibition = >83 mm = complete eradication), lemon myrtle (65 mm), mountain savory (62.5 mm), cinnamon bark (Cinnamomum verum) and melissa (60 mm), and thyme (Thymus vulgaris) at 57 mm . In another study, zones of inhibition for eucalyptus against 14 strains of MRSA were comparable to that of vancomycin !
There are so many amazing things about eucalyptus essential oil and so much science backing it up that I couldn't possibly go into it all here, but if you're interested I suggest to read the paper at the link in footnote 1.
The only possible drawback I could find in the use of EO is that it is mildly anti-tussive in large doses, meaning that it may suppress a cough. It does this by reducing movement of the cilia (little hairs) lining the airways of our lungs and sinuses . It is not known how strongly an effect this has on humans (studies have only been done on this subject in lab studies) but I have noticed in myself a slight reduction in my urge to cough, even when I feel there may be mucus in my lower airways. I mentioned this to my CF doctor and she didn't seem that concerned about it. She said that what matters more is how I feel, how I sound under the stethoscope (clear!), and the improvement in my PFTs. This effect may vary from person to person, but it's a good thing to watch out for and keep in mind.
Tea Tree Oil
The tea tree (Melaleuca alternifolia) is also a native tree of Australia and has several similar chemical actions and constituents to eucalyptus. It is highly antimicrobial and is kind of a "go to" oil in the herbal first aid kit for its antiseptic properties. It is now commonly used in antiseptic hand washes, toothpaste, and cosmetics. It is considered to be more antibacterial than many eucalyptus species but does not have eucalyptus' immunomodulating effects. Although it has a small amount of 1,8-cineole, its main constituent is terpinen-4-ol, which is credited as giving TT most of its antimicrobial effects . Research has proven it to be effective against 27 bacterial and 24 fungal strains, as well as some viruses and protozoa . In one study it was shown to have powerful antibacterial effects on biofilm-grown MRSA . There have been several case reports of prolonged tuberculosis infections (a type of mycobacterium) being cured by inhaling several days of TT by steam inhalation. As was previously mentioned, TT is one of the few oils effective against multi-drug-resistant Pseudomonas  and other gram-negative bacteria. In one study, tea tree oil was moderately effective against MRSA with a zone of inhibition of 45 mm (compared to E. citriodora at 50 mm, or lemongrass at >83 mm) .
Tea tree oil does have anti-inflammatory properties as well. Studies have shown that it downregulates the production of pro-inflammatory cytokines (chemicals produced by a certain part of the immune system) and reduces inflammatory oxidation in animal studies when inhaled . Furthermore, TT is highly antifungal and very effective against Candida yeast infections, inhibiting its ability to mutate from yeast to hyphae form. TT has also been shown to be bactericidal against MRSA biofilms .
Lemongrass is actually a genus (Cymbopogon) of 45 species of grasses native to southern Asia. It has been used as a medicinal and culinary herb for centuries, and can also be used to repel insects (citronella grass is a species within this genus). In folk medicine, lemongrass is used not just as an antiseptic but also to calm the mind, reduce anxiety, and improve mental clarity. It is also used in many south Asian cuisines. Cymbopogon citratus is the most commonly used species for its medicinal oil. The species are differentiated by their chemotypes, meaning that they are categorized by their dominant chemical constituents, which can vary significantly between lemongrass species. Its most prevalent chemical constituents are citral and geraniol . Lemongrass oil (LG) is strongly antimicrobial, especially against bacteria but also against fungi, viruses, and even parasitic worms. One study found that out of 14 different essential oils tested including some of the strongest like cinnamon and thyme, lemongrass oil was the most effective against the H. influenzae, a gram-negative bacteria . LG has been shown to have anti-cancer and anti-inflammatory effects as well. It is also effective against Aspergillus and Candida fungal (mold and yeast) infections. LG has extraordinarily high antioxidant powers .
In a study comparing the antibacterial power of essential oils against drug-resistant bacteria, LG had the strongest bactericidal effect against MRSA compared to eucalyptus and TT. Interestingly, all three essential oils were more bactericidal against these drug-resistant bacteria than both 70% ethanol (alcohol) and chlorhexidine (a commonly-used chemical antiseptic) . Furthermore, lemongrass oil proved to be more antibacterial against all bacteria tested (including two strains of Staphyloccocus aureus) than any of its isolated constituents (citral, geraniol, and myrcene), proving once again that whole oils are more powerful than chemical isolates. This study also showed that LG is effective against Staph biofilms , which is an incredibly important distinction to make, since the chronic infections that we CFers get in our lungs become intractable precisely because of the development of bacterial biofilms. Many in-vitro studies only test effectiveness of antibacterial substances against planktonic bacteria, but biofilm-inhabiting bacteria is a whole different beast, and biofilms are what make chronic infections so resistant to antibiotics. All this said, lemongrass seems to me one of the most powerful oils against MRSA, and while it is pretty irritating it is less so than several of the other oils that have similarly powerful antibacterial effects (i.e. cinnamon and thyme).
As I mentioned, I tried cinnamon leaf oil but it was too irritating for me to continue. Some essential oils are not safe to nebulize nor apply topically (without being diluted) due to the potential damage they can do to sensitive human tissue. Some oils can literally burn the skin or cause an allergic reaction in sensitive people. I was interested in cinnamon because several studies have shown that cinnamon (Cinnamomum verum and several other species within Cinnamomum genus) and its major constituent, cinnamaldehyde, are extraordinarily antimicrobial. While I do not think nebulzing cinnamon is a good idea because it's so irritating, I do think it has a place in the treatment of skin and external tissue infections when properly diluted in a carrier oil like coconut or olive oil. It is also safe to use in an aromatherapy diffusor that emits the scent of it throughout the room, and can be especially useful during cold and flu season. It may also be an effecive antiseptic for cleaning surfaces.
One study showed that cinnamon bark oil was the most effective oil at the lowest concentrations against Staph and several other bacteria compared to clove, cardamom, and cumin oils . Another in-vitro study used a model of essential oil inhalation showing that out of 14 oils tested, cinnamon and thyme oils were the strongest antimicrobial oils, especially against Staph and H. influenzae . Cinnamaldehyde in cinnamon and thymol in thyme are considered to be some of the strongest bactericidal constituents in essential oils.
Thyme oil is another very promising essential oil. There are about 350 species within the Thymus genus native to Europe, North Africa, and Asia. In the scientific literature, there has been significant study on a handful of these species and their major constituents. There have been several studies on Thymus vulgaris, Thymus zygis, and Thymus serpylum, but most research has been done on specific chemotypes of T. vulgaris. The major constituents of thyme that are the most well-studied are thymol, geraniol, eugenol, carvacrol, and linalool. Thymol, carvacrol, and eugenol have very strong effects against MRSA . Thymol chemotypes of thyme are the strongest antimicrobial oils that I have read about in the scientific literature , and are stronger than vancomycin against MRSA in vitro .
I have been hesitant to try inhaling thyme because I have been warned by multiple herbalists that although thymol is a very effective antibacterial constituent, it is toxic to the kidneys in high doses. Inhaling very small daily doses of EOs used for a short period of time is safer than ingesting them, and will likely not cause harm to the kidneys. But EO's potential toxicity to the kidneys is something important to keep in mind (especially since I've had kidney troubles caused by IV antibiotics in the past). A solution to this problem is to choose chemotypes of thyme that do not have much thymol in them, and instead have more linalool, geraniol, or alpha-terpineol. There is some research being conducted currently by a well-known aromatherapist, Maggie Tisserand, on the use of a specially formulated thyme blend called "benchmark thyme" for therapeutic use against MRSA infections. Benchmark thyme oil is unique because it harvests certain chemotypes of thyme at certain times of the year to ensure a specific balance of chemical constituents that are effective against MRSA . Thyme may be irritating to inhale, but benchmark thyme is formulated to be as gentle as possible while still maintaining its bactericidal powers. The article I wrote on my experiments with benchmark thyme is written at this link.
Essential oils are very concentrated, very powerful herbal medicines that need to be used with caution. Improper use of essential oils can have serious side effects including allergic reactions and topical burns. Essential oils need to be used in very small doses, ideally 1-5 drops per nebulization. The stronger the oil, the lower the dosage. Not all essential oils are appropriate for use in a nebulizer, as I have stated above. Some of them are too irritating and may temporarily worsen respiratory symptoms. The safest essential oils to nebulize, in my opinion, are lavender (excellent anti-inflammatory and calming to the nerves), eucalyptus, peppermint, and tea tree oil. Essential oils must always be diluted, and nebulizer cups must always be washed thoroughly with soap and water after use. If essential oils are left in the neb cup for too long they can corrode the plastic. Make sure to replace your neb cups every 3-6 months and wash daily with hot soapy water.
I recommend to always take a break from essential oil therapy. Using any high-potency medicine every day over a long period of time runs the risk of causing one to develop sensitivities or allergies to it. Thus I recommend to my clients to nebulize essential oils for no more than two weeks at a time, then take a 1-2 weeks break. It's also a good idea to change up the oils every two weeks or so, both to change the game on the bacteria and to reduce the risk of developing sensitivies.
Some individuals are more sensitive than others, especially if you already have allergies to other things. If essential oils cause respiratory irritation or other negative symptoms, stop them immediately. For sensitive people or small children I often recommend inhaling essential oils through an aromatherapy diffusor because this provides lower doses. I find it especially beneficial to have an aromatherapy diffusor running near the head at night when one is sleeping in bed. I have recommend clients use rectal suppositories when their lung tissue is too sensitive or nebulization and this seems to be very effective. Suppositories may also be a good choice for children.
Though I nebulized essential oils on and off for several years, I stopped nebulizing them about three years ago because I noticed they worsened my pleurisy (inflammation of the lung's pleura). I am a person prone to lung collapses, so for me I feel nebbing essential oils may cause too much irritation which may worsen my pleurisy and potentially make me more vulnerable to lung collapses. If you experience pleurisy regularly or have had lung collapses before, nebulizing essential oils may not be a good choice. Instead I would recommend an aromatherapy diffusor, topical use, or rectal suppositories.
The body processes many essential oils through the kidneys and liver, so if you have advanced kidney or liver disease it may not be safe for you to nebulize essential oils, in which case using them in an aromatherpay diffusor would be safer.
In addition, it is critcical to use sterile water or saline to dilute essential oils in a nebulizer cup. Tap water, bottled water, or well water is not suitable because all of those could contain microbes that might infect the respiratory system (even if that water is safe to drink). Many pharmacies in North America and Europe sell sterile water or saline, but if you do not have access to these, you may make your own sterile water by boiling purified water for 5 minutes and storing it in small, sterilized glass containers in the fridge. Every time you open one of these containers, the liquid runs the risk of being un-sterilized, that's why it's important to use small containers of water and to keep them in a clean place. We do not want to inadvertantly expose our lungs to extra pathogens!
The only thing most conventional doctors know about inhalation of essential oils is a thing called "lipoid pneumonia". There have been a handful of case reports in the last several decades of people inhaling true oils (such as olive oil, mineral oil, or skin creams) and this causing a serious condition called lipoid pneumonia. Although essential oils are called "oils", they are in fact not at all like the oils that we consume in food or apply topically in hand creams and such. Essential oils are made up of extremely small volatile organic compounds that are absorbed through our tissues too easily to run the risk of causing lipoid pneumonia. I don't believe there is a risk of developing lipoid pneumonia from inhaling essential oils in the small doses I'm suggesting above. I read all of the case reports on the subject published in the last few decades (there are only a handful) and none of them related to accounts of nebulizing or inhaling pure essential oils as I have described in this article. I should also be clear that we must never nebulize or inhale essential oils if they are diluted in a carrier oil. That could cause lipoid pneumonia, but it would be the carrier oil causing it, not the essential oils themselves.
Lastly, be aware that many essential oils sold on the market are low quality or adulterated. Do not buy essential oils sold at grocery stores or local pharmacies - those are sure to be of the lowest quality. When it comes to essential oils, you get what you pay for. We want to use the highest quality oils if we're going to have them contact such sensitive tissue as the lungs. Beware of multi-level marketing companies such as Young Living and DoTerra. They market their products as high quality but it's not always true, plus they trick people into spending a lot of money on them in unethical financial schemes. Instead, I suggest essential oils from Aromatics International. I have no affiliation with Aromatics International, but I trust their company because they often source from organic or sustainably wildcrafted plants and have batch records of every oil published on their website. These batch records give the GC/MS reports of every oil outlining what specific chemicals are contained in them and in what ratio. If you wish to purchase oils from a different company, make sure that they make their GC/MS reports freely available to the public and that they source from organic or sustainably wildcrafted plants (we don't want to be inhaling pesticides and toxic chemicals).
In conclusion, the inhalation of essential oils was a revelation to me and for several years helped me control my lung infections and reduce (but not eliminate) my need for antibiotics. If properly used, nebulizing essential oils has few side effects and none of the negative impacts of antibiotics on the gut microbiota. If you try nebulizing essential oils, please be sure to read my section of safe usage and things to avoid.
Good luck and be well!
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 Immune-modifying and antimicrobial effects of eucalyptus oil and simple inhalation devices. <http://www.altmedrev.com/publications/15/1/33.pdf>
 The Thyme is Right. <http://www.benchmark-thyme.com/userfiles/file/FHT%20Article%20Benchmark%20Oil%20APRIL%202011%20without%20cover.pdf>
 Antibacterial activity of essential oils and their major constituents against respiratory tract pathogens by gaseous contact. <http://jac.oxfordjournals.org/content/47/5/565.full>
 The ongoing battle against multi-resistant strains: in-vitro inhibition of hospital-acquired MRSA, VRE, Pseudomonas, ESBL E. coli and Klebsiella species in the presence of plant-derived antiseptic oils. <http://www.ncbi.nlm.nih.gov/pubmed/23199627>
 Inhibition of methicillin-resistant Staphylococcus aureus (MRSA) by essential oils. <http://aromatherapyliving.com/docs/MRSA_Research_Young_Living_Weber_Univ.pdf>
 Tea Tree Oil. <http://www.sigmaaldrich.com/life-science/nutrition-research/learning-center/plant-profiler/melaleuca-alternifolia.html>
 The effect of lemongrass oil and its major components on clinical isolate mastitus pathogens and their mechanisms of action on Staphyloccocus aureus DMST 4745. <http://www.ncbi.nlm.nih.gov/pubmed/21316719>
 Lemongrass. <http://www.sigmaaldrich.com/life-science/nutrition-research/learning-center/plant-profiler/cymbopogon.html>
 Antibacterial effect of essential oils from two medicinal plants against MRSA. <http://www.ncbi.nlm.nih.gov/pubmed/19576738>
 Antimicrobial activity of the bioactive components of essential oils from Pakistani spices against Salmonella and other multi-drug resistant bacteria. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3853939/>
 In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylococci growing planktonically and as biofilms. <http://jmm.sgmjournals.org/content/55/10/1375.full>
Mica McDonald (they/he) is a clinical herbalist, nutritionist, ecologist, and writer living in Abenaki territory (Vermont).