WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
Eucalyptus is a genus of plants that contains more than 900 species.1 The plants are native to Australia and come in a number of sizes, from shrubs to tall trees. They’re known for growing rapidly: One of the largest is the giant gum tree that can grow to up to 300 feet.
A distinctive feature of eucalyptus is its bark, which the tree sheds as it grows. Some will shed much of their bark while others are completely covered with it. Although they grow tall, some thrive in containers. They can also be planted annually.2 Each part of the eucalyptus plant can produce essential oils, but it's the leaves that are the richest source.
Better Homes and Gardens writes that on extremely hot days, a stand of trees may appear as if a fog is hanging over them. This is caused by the oil vaporizing in the heat. The eucalyptus offers diverse medical benefits, almost as wide and divergent as the varieties.
Eucalyptus Oil Reduces Inflammation in Lung Tissue
Your mom knew best when she rubbed eucalyptus oil on your chest when you had a cold or cough. This is because researchers have found that the essential oils have antiviral activity and may reduce inflammation in the lungs.3 Eucalyptus contains 1,8-cineol, also known as eucalyptol, which is the major monoterpene responsible for suppressing cytokine production in human monocytes.4
The authors of one study looked at the anti-inflammatory effect of 1,8-cineol in comparison to prednisolone that was equal in potency. They tested it on 32 patients who had severe asthma, using a double-blind, placebo-controlled trial. The researchers found that 75% of those receiving cineol from eucalyptus versus 25% who got a placebo were able to reduce their oral steroids.
When measured against pulmonary inflammation in an animal model, other researchers found that eucalyptol could reduce the number of inflammatory cells and decrease protein content in bronchoalveolar lavage fluid, providing “evidence … [for] its potential for the treatment of acute lung injury.”5
Still other investigators found that eucalyptus oil could attenuate induced lung injury and inhibit pro-inflammatory cytokine production, offering evidence that it may have potential as a drug treatment for chronic obstructive pulmonary disease.6
Clinical evidence supports these theories; however, the mechanism of action and the bioactive compounds that are responsible have not been well studied. This prompted one team to look into the primary component of the oil, 1,8-cineol, in a lab study.7
They found that the anti-inflammatory activity is due to down-regulating pattern recognition receptors, which play an important role in systemic infections.8
Each of these actions are important in supporting the body’s efforts in fighting viral infections. A second benefit may be the plant’s ability to suppress inflammatory cytokine production in an infection where hyperactive immune responses and cytokine storms trigger lung and organ damage that may lead to death.
Eucalyptus Reduces Inflammation and Pain
The effects of eucalyptus oil on inflammation and pain have also been of interest to the medical community. One group analyzed the physiological and psychological parameters of 32 individuals. They found that a combination of peppermint oil, eucalyptus oil and ethanol could induce muscle and mental relaxation, but it did not influence pain sensitivity.9
Researchers have had different results depending on the genus of eucalyptus used. In Brazilian folk medicine, a variety are included in treatment for conditions such as bronchial infections, colds, flu and fever. In one study, a team of researchers used an animal model to look at the anti-inflammatory and analgesic effects of three species.10
Eucalyptus induced both effects, suggesting that the essential oil exerted central and peripheral reductions in pain. This supports further investigation for the possible development of pain medications derived from eucalyptus essential oils.
Eucalyptus oil has also been evaluated in the treatment of pain after a total knee replacement.11 A group of individuals were given either eucalyptus inhalation treatments or almond oil inhalation treatments. Researchers measured blood pressure, heart rate and pain ratings before and after the inhalation therapy. On all three days the ones who inhaled eucalyptus reported less pain.
Additionally, on the second day, the intervention group — the ones receiving eucalyptus — had significantly lower blood pressure. Researchers noted that this suggested that aromatherapy involving eucalyptus may be an effective intervention for pain relief after a total knee replacement.
More Benefits to Eucalyptus Essential Oil
The essential oil from the eucalyptus tree is produced from dry leaves. In past decades, diluted oil has been used for a number of reasons, including addressing inflammatory conditions such as bronchitis and respiratory infections.12 Traditional Aboriginal medicine involved the use of eucalyptus to heal wounds and fungal infections.
In one study, researchers evaluated the effects of eight eucalyptus species found in Tunisia. They were interested in its antimicrobial properties for treating bacterial isolates such as, Klebsiella pneumoniae, Staphylococcus aureus, Hemophilus influenza and Pseudomonas aeruginosa.13
Eucalyptus odorata had the strongest activity against Staphylococcus aureus, Hemophilus influenzae and streptococcus pneumoniae. It also had the most cytotoxic effect. However, the eucalyptus variety with the best antiviral activity was eucalyptus bicostata.
It’s important to know that eucalyptus essential oil may be used topically or in a vaporizer, but it should not be ingested. Some mouthwashes contain eucalyptus with other essential oil to help reduce the buildup of plaque and to treat gingivitis. Its antiseptic properties help kill oral bacteria that lead to the buildup of plaque.
The oils have also demonstrated positive effects against headaches and neuralgia, as well as in the treatment of skin conditions such as herpes, lice and insect bites.14 In general, eucalyptus essential oil is safe to use, but you must follow specific precautions.
Do a patch test to be sure you don't have an allergic reaction. The oil should never be given to children under age 2 or used as a chest rub or on the nose of a baby.15 Women who are pregnant and breastfeeding should avoid eucalyptus because there’s not enough evidence regarding its safety in that population.
Weakened Immune System Raises Your Risk of Viral Infections
When you spend more time indoors, being inactive and munching on foods that don’t support your immune system, you may experience an increase in your risk of infections and chronic disease. This can happen even if you don’t have a primary immune deficiency.
Primary immune deficiency disorders allow infection to happen more frequently and more easily.16 Some forms are mild and may be undiagnosed for years. People who have a weaker immune system, whether from a primary condition or as a result of lifestyle choices, will have more difficulty clearing infections.
Those who have chronic diseases such as diabetes, liver or kidney disease, as well as those who’ve undergone organ transplants and those receiving chemotherapy or radiation treatments, also have weakened immune systems that can lead to longer illnesses and hospitalizations.17 Your food choices and eating patterns have a significant impact on your ability to withstand infection, however.18
There are a few things you might unknowingly be doing that impact your body’s defenses. These include sitting for long periods of time, which has been linked to diabetes, heart disease and early death.19
However, just as inactivity is a problem, overtraining or getting too much exercise without enough recovery, can also impact your immune system. A lack of stress management, excessive alcohol use and sleep deprivation are additional factors that impact your body’s ability to fight infections.
Take Care to Support Optimal Health
I've been writing for many years about the strategies you can use to help support your immune system. You'll find a list of specific ways to do so on my Coronavirus Resource Page.
Simple things like frequently washing your hands using the proper technique help reduce the spread of any infection and reduce your exposure to bacteria, viruses and fungi. Researchers have found that individuals with high blood pressure and diabetes have a higher risk of severe disease, so it is essential to look into these and take steps to gain control over them in your overall health management.
Many comorbidities are the result of metabolic dysfunction. This means that when you address insulin resistance, you will likely have a positive impact over many other chronic conditions.
During all times of the year, it’s necessary to get plenty of sleep to support your gut microbiota and brain health. You also need to get enough daily exercise because it has a positive effect on the immune system, helps promote better sleep and improves mood.
Another vital strategy in protecting yourself from COVID-19 and other infectious diseases is to raise your vitamin D levels to between 60 ng/mL and 80 ng/mL. On May 11, 2020, Medscape.com released a video featuring Dr. JoAnn E. Manson from Harvard Medical School, in which she discussed the protective role that vitamin D has against COVID-19.20
She is not alone in her recommendations for attaining and maintaining adequate levels of the vitamin, as researchers suggest it plays an important role in the risk of getting the infection as well as the severity of an illness.
In my article, “Are Stay-at-Home Orders Decimating Vitamin D Levels?” you'll find further evidence relating to the higher mortality rates researchers are finding in those who have a vitamin D deficiency. For an in-depth discussion of the impact that vitamin D levels have on risk and how to optimize those levels, see “Your Vitamin D Level Must Reach 60ng/mL Before the Second Wave.”