Ranked as the world’s first traded oil, essential oil of Eucalyptus is obtained from various species of the Eucalyptus tree, native to Australia, that belongs to the Myrtaceae family. [1]
E. globulus oil is one of the most commonly traded eucalyptus oils, and highly represented in international pharmacopoeias, and is used widely in Japan and Europe for aromatherapy, owing to its medicinal properties. [2]
Traditionally, the oil has been used for its antimicrobial, insect repellent, cold-curing, cancer-treating, anti-diabetic properties, and further research is exploiting its use for other health benefits such as pain relief and wound care.
Its demand has also become high in the cosmetic and soap industries. [3]
Eucalyptus oil can be either extracted via steam distillation or hydrodistillation, essentially from the leaves of E. citriodora, E. globulus, E. camaldulensis, E. grandis species amongst many others. [4]
Folklore remedies, now backed with scientific evidence, suggest the efficacious use of eucalyptus oil for treating various respiratory, inflammatory, pain-related, dental and periodontal disorders due to its antimicrobial, anti-inflammatory, analgesic properties.
Major constituents of the oil such as cineole and macrocarpals impart to the oil antimicrobial and anticancerous properties. [5]
Eucalyptus oil is highly poisonous if ingested and may lead to death if taken even in very small quantities. It can lead to poisoning as well causing CNS depression and ataxia.
It is advised that pregnant and lactating women do not use the oil, and children should avoid its use.
Topical application or inhalation of the essential oil may lead to contact dermatitis, heartburn, nausea, vomiting, headache and even back pain.
Healing Solutions, based in Arizona, USA, is a manufacturer of natural organic essential oils. The therapeutic grade essential oil has a net volume of 10 ml. The key ingredient includes 100% pure therapeutic grade eucalyptus essential oil.
Some of the key USPs of the product are:
Manufactured in a GMP certified facility as per FDA standards
Pure and rigorous quality testing controls for best results
Money refund on customer dissatisfaction
Here are key Pros and Cons based on Analysis of Customer Reviews-
Most users found the product quality potent and satisfying
Quick noticeable results for most users
Highly recommended by most users
Easy to dispense for most users
Value for money
Most users found the scent appealing
Most consumers lauded the longevity of the product
Most consumers found the product packaging premium and satisfying
Few users found product quality and smell inconsistent
ArtNaturals, based in USA, is a manufacturer of organic essential oils, skin care and beauty products. The therapeutic grade essential oil has a net volume of 118 ml.
The key ingredient includes 100% pure therapeutic grade eucalyptus essential oil.
Some of the key USPs of the product are:
Ideally suitable for DIY oils
Pure and rigorous quality testing controls for best results
Unadulterated, therapeutic grade, vegan and gluten-free
Full amount refund on customer dissatisfaction
Here are key Pros and Cons based on Analysis of Customer Reviews-
Most users found the product quality potent and satisfying
Quick noticeable results for most users
Highly recommended by most users
Easy to dispense for most users
Value for money
Most users found the scent appealing
Most consumers lauded the longevity of the product
Most consumers lauded the multiple benefits on application of the oil
Few users found product quality and smell inconsistent
The phytochemical constituents of the eucalyptus oil include monoterpenes, oxygenated monoterpenes and oxygenated sesquiterpenes. [6]
1,8-cineole is a major constituent that is present along with macrocarpals (phloroglucinol – sesquiterpenes), monoterpenes (D-limonene, -pinene, -pinene, p-cymene), alkaloids, eucalyptin, phenols and flavonoids. [7]
Eucalyptone G, a phloroglucinol derivative, exhibits a strong bactericidal effect against gram-positive and gram-negative bacteria. [8]
1,8-cineole also has a potent antimicrobial effect and is used to kill microbes that have acquired resistance to multiple antibiotics. [9]
Research shows that the expression of many genes may be downregulated or upregulated due to eucalyptus oil, that causes abnormal structures and physiological function disorders, thus making the oil a potent antifungal agent. [10]
The hydrolysable tannins and rich monoterpenoid content of eucalyptus oils possess antioxidant properties [11], whereas euglobol and macrocarpals have promising anti-carcinogenic effects.[12],[13]
Because of the cineol and terpineol content, that is volatile in nature, eucalyptus oil gets easily absorbed into the tissues and muscles and helps to relieve pain and block nerve signals. [14],[15]
1,8-cineole is also responsible for relieving cough, expelling sputum and relax respiratory muscles in people suffering from respiratory disorders [16] and is also a strong insect repelling agent along with other phenolic constituents of the oil. [17]
Key Health Benefits of Eucalyptus Oil
Eucalyptus oil can Treat many Respiratory Ailments
Owing to the anti-inflammatory effects of eucalyptus oil, it is used to treat many acute and chronic respiratory disorders like asthma, bronchitis, rhinosinusitis, etc.
Confidence: High
Asthma
In an ex vivo study carried out in patients suffering from bronchial asthma, they were given 200mg of 1,8-cineol thrice daily.
It was seen that leukotriene B4 and prostaglandin E2 synthesis from monocytes (responsible for causing asthma) of these patients was inhibited with treatment. [18]
In another clinical trial carried out on 32 patients suffering from steroid-dependent severe asthma, it was seen that 200mg of eucalyptol (1,8-cineole) given thrice daily for 12 weeks was able to reduce the steroid dependence and dosage of the steroid medications taken by these patients, thus proving to be an effective mucolytic agent to treat asthma. [19]
A clinical trial carried out on 247 patients proved that 200 mg of cineol (a major constituent of eucalyptus oil) supplementation, thrice daily, can improve forced expiratory volume, asthma symptoms and general quality of life alongside treating dyspnea and cough. [20]
Chronic Obstructive Pulmonary Disease (COPD)
In a clinical study carried out in 242 patients suffering from COPD, administration of 200 mg of cineole, thrice daily, was able to delay the worsening of the respiratory ailment, along with significantly improving lung function, dyspnea, and quality of life associated with COPD. [21]
Bronchitis
In a double-blind trial carried out in patients suffering from acute bronchitis, it was seen that treatment with 200 mg of cineole, thrice daily over a period of 10 days, was able to significantly reduce dyspnea, coughing and secretion of cough, thoracic pain and improve general lung function. [22]
In a multicentre trial carried out in 6 health centres, a spray containing 5 aromatic essential oils of Eucalyptus citriodora, Eucalyptus globulus, Mentha piperita, Origanum syriacum, and Rosmarinus officinalis, was tested.
The spray was applied 5 times a day for 3 days.
A significant improvement in symptoms such as sore throat, hoarseness, cough, stridor, mucous secretion and fever was observed as compared to the placebo group. [23]
Rhinosinusitis
In a study carried out on 152 patients suffering from acute non-purulent rhinosinusitis, two 100mg capsules of cineole were given thrice daily for a period of 7 days.
It was seen that primary symptoms such as headache on bending, sensitivity of pressure points, nasal obstruction, rhinological secretion and secondary symptoms like redness, oedema and dryness of mucosa improved significantly. [24]
Miscellaneous
In a study carried out on young girl athletes, it was observed that the inhalation of eucalyptus oil essence was able to improve the active pulmonary volume, reduce diastolic blood pressure, and effectively reduce muscle pain and cramps. [25]
Eucalyptus oil is used to treat many Dental Conditions and Maintain overall Oral Hygiene
Confidence: High
A double-masked clinical study showed that 149 patients suffering from gingivitis were given chewing gum enriched with eucalyptus oil in either high (0.6%) or low (0.4%) concentrations.
Two tablets of chewing gum were chewed for 5 minutes, 5 times daily, for a period of 12 weeks. A significant improvement in plaque accumulation, gingival inflammation, bleeding and periodontal probing depth was observed. [26]
A study carried out on 74 subjects showed that using a eucalyptus oil mouthwash, twice daily for 14 days, was able to significantly reduce plaque levels and maintain the overall oral hygiene, as effectively as the standard chlorhexidine mouthwash, without causing any adverse effects. [27]
Research has shown that Listerine, a mouthwash containing thymol, menthol, eucalyptol and methyl salicylate, is effective in clearing dental plaque and effectively treating gingivitis, when used to rinse the mouth twice daily, for a period of 6 months. [28],[29],[30]
An in vitro and in vivo study showed that essential oil obtained from Eucalyptus camaldulensis was more effective in eradicating the biofilms of the bacteria Streptococcus mutans and Streptococcus pyogenes as compared to the Mentha spicata oil and chlorhexidine.
These bacterial biofilms that are responsible for causing various oral infections and dental problems, are hard to eradicate. Thus Eucalyptus oil can be considered as a novel anticaries treatment. [31]
Eucalyptus oil is a Potent Analgesic
Confidence: High
In a double-blind trial carried out on 32 subjects, it was seen that application of eucalyptus oil along with peppermint oil and ethanol was able to significantly reduce headache, improve the mood as indicated by contingent negative variation and produce a mental-relaxing effect. [32]
Fifty-two patients suffering from osteoarthritis and having undergone total knee replacement surgery, were made to inhale 3% (v/v eucalyptus oil), for 30 minutes.
Not only did the aromatherapy decrease the pain significantly but also effectively reduced blood pressure, producing a relaxing effect. [33]
Eucalyptamint, a counterirritant ointment of eucalyptus oil, when applied to the skin, was able to significantly increase blood flow to the area of application and increase muscle and skin temperature after 30 minutes, according to a study, thus proving its use as pain relief and a passive form of warm-up for athletes. [34]
In another clinical trial carried out on patients suffering from neuropathic pain associated with diabetes, it was seen that aromatherapy massage with essential oils of eucalyptus, rosemary, geranium, lavender and chamomile was able to significantly alleviate the pain. [35]
An in vivo study carried out in rat models for pain and inflammation showed that intraperitoneal administration of essential oils obtained from Eucalyptus citriodora, Eucalyptus tereticornis, and Eucalyptus globulus were able to induce a significant analgesic and anti-inflammatory effect owing to the presence of mainly eucalyptol. [36]
Eucalyptus oil is Effective as an Insect-Repellent and Rodenticide
Confidence: High
In a clinical trial, the repellent activity of Eucalyptus maculata citrodion oil was tested at 40% and 75% concentrations in coconut oil, against mosquitoes of Mansonia species in Gambella, western Ethiopia.
It was seen that eucalyptus oil showed significant repellent activity and reduced the mean number of mosquito bites significantly. [37]
Another study showed that a commercial mosquito repellent called Zero Bite contained a blend of microcrystalline waxes, mineral oils, natural flavours, Olibanum oil, Eucalyptus oil, Geranium oil, Citronella oil and Isopropyl myristate.
It was seen that topical application of this repellent gave overall protection against mosquito bites and the effect lasted for more than 5 hours in comparison to another insect-repellent containing a petroleum jelly formulation containing diethyl toluamide (DEET). [38]
Another field evaluation study showed that application of eucalyptus oil based product was able to prevent mosquito bites of and repel Anopheles darlingi, a vector of malaria in Bolivia, with 96.89% efficiency, for a period of 4 hours. [39]
Essential oil of Eucalyptus grandis x E. urophylla exhibits an antifeeding effect in dose-dependent manner for pest insects such as Spodoptera litura Fabricius and Helicoverpa armigera Hubner. [40]
Eucalyptus oil is useful in Treating Lice and Dandruff
Confidence: Moderate
In a randomized multicentered trial, it was seen that treatment with Australian Eucalyptus oil and Leptospermum petersonii, applied thrice at a 7-day interval, was able to eliminate lice infestation twice as effectively as pyrethrins and piperonyl butoxide. [41]
In the same study but different trial parameters, it was seen that single application of Australian Eucalyptus oil and Leptospermum petersonii was able to exhibit a 100% pediculicidal effect. [42]
Another study showed a 3.3% pediculicide activity of a solution of Eucalyptus oil and lemon tea tree oil.[43]
An in vitro study carried out to analyze the effect of eucalyptus essential oil on dandruff causing fungi Malassezia furfur showed that its growth was inhibited strongly, owing mostly to the presence of eucalyptol in the oil.
Thus eucalyptus oil can be used as an anti-dandruff drug.[44]
Eucalyptus oil possesses Antibacterial Activity
Confidence: Moderate
In an isolated case of a 28-year-old woman suffering from tuberculosis, it was seen that aromatherapy with 3 ml eucalyptus oil added to 500 ml of boiling water was able to ameliorate malaise, appetite, cough and weight loss associated with TB, within 10 days. [45]
In another case, two humans infected with MRSA were treated with PolytoxinolTM (eucalyptus, tea tree, thyme, clove, and lemongrass extracts in ethanol), applied topically, twice daily. The people were treated in 5 days and 3 weeks, respectively. [46]
Multiple in vitro studies have shown that many bacteria such as S. aureus, S. epidermidis, E. faecalis, B. subtilis [47], Haemophilus influenzae, H. parainfluenza, Stenotrophomonas maltophilia [48], Mycobacterium tuberculosis [49], Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Streptococcus mutans, Streptococcus sobrinus [50] show high sensitivity to eucalyptus essential oils.
K. pneumoniae, P. mirabilis, P. vulgaris, E. coli, P. aeruginosa, S. typhi [51], S. pneumoniae, S. agalactiae, S. pyogenes [52] are the bacteria that show mild or very mild sensitivity to eucalyptus oils.
A study carried out on multiple isolates of bacteria from 200 clinical specimens of patients suffering from respiratory disorders showed that Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae and Haemophilus influenzae had high sensitivity towards eucalyptus oil. [53]
Research also showed that a multidrug-resistant strain of Acinetobacter baumannii, responsible for causing respiratory infections, was sensitive to E. camaldulensis essential oil at a low minimum inhibitory concentration, owing to the presence of spatulenol, cryptone, p-cimene, 1,8-cineole, terpinen-4-ol and β-pinene. [54]
Eucalyptus oil may be used to Treat Fungal Infections
Confidence: Moderate
In a study carried out in 50 patients suffering from either tinea pedis, tinea corporis or tinea cruris, it was seen that topical application of an herbal preparation containing 1% eucalyptus oil, twice daily for 3 weeks, was able to cure the skin infection in 60% of the patients and improve the symptoms in 40% of the patients. [55]
The same study when carried out in vitro showed that essential oil of Eucalyptus pauciflora was able to exhibit potent antifungal activity against potential human pathogens such as Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton mentagrophytes, T. rubrum, T. tonsurans and T. violaceum, at a concentration as low as 1.0 µl/ml. [56]
Fungi like Candida albicans, Aspergillus flavus and Aspergillus niger highly sensitive to the antifungal property of E. sideroxylon and E. torquata essential oils. [57]
Another study showed that eucalyptus oil showed the strongest antifungal activity of 80.87% against biofilm of Candida albicans, eradicating it successfully at a low minimum inhibitory concentration, compared to the essential oils of peppermint, ginger grass and clove. [58]
Proliferation of pathogenic fungi such as Fusarium oxysporum, Pyriculerie grisea, Glorosprium musarum and Phytophthora capsici is also inhibited by essential oil extracted from the leaves of Eucalyptus grandis x E. urophylla. [59]
Eucalyptus oil may be used for Healing Wounds
Confidence: Moderate
One ml of nanoemulsion of Eucalyptus globulus oil was applied topically on Wistar rat model for wounds.
It was seen that there was rapid progress in the contraction of the wound after day 10, and a 100% recovery was observed in 16 days.
This may be attributed to the wound healing and antimicrobial effect of eucalyptol. [60]
Eucalyptus oil loaded onto alginate fibre wound dressing has also been deemed to be effective for healing wounds due to the antimicrobial activity of eucalyptol present in the eucalyptus oil.
In another study, the effect of eucalyptus oil was seen on vascular permeability, which is essential for the healing process of wounds.
Eucalyptus oil increased the capillary permeability as effectively as histamine. [61]
Eucalyptus oil may be an Anti-Diabetic
Confidence: Moderate
An in vivo study carried out in STZ-induced diabetes rat models, incorporation of 62.5g/kg eucalyptus oil in their diets showed a significant improvement in hyperglycemia, polydipsia, polyphagia, and compensated weight loss of diabetic rats. [62]
An in vitro study proved the antioxidant effect of eucalyptus essential oil and its ability to inhibit α-amylase and α-glucosidase, thus causing a decrease of the glucose absorption speed and postprandial blood glucose levels, thus exhibiting an anti-diabetic effect. [63]
As per a research article published in the Glasgow Medical Journal, the author used a eucalyptus oil infusion to treat many patients suffering from diabetes, and claimed that their symptoms such as pruritus, glycosuria, thirst and boils, disappeared within a matter of months. [64]
Eucalyptus oil may be a Potential Anti-Cancer Agent
Confidence: Low
An in vitro study showed that eucalyptus essential oils obtained from Eucalyptus sideroxylon and Eucalyptus torquata were able to show cytotoxic effects in the Human breast adenocarcinoma cell line (MCF7).
An in vitro study carried out on human Burkitt’s lymphoma Raji cell line andEBV-negative Burkitt’s lymphoma BJAB cell line, showed that eucalyptus essential oils extracted from 6 different species of the plant, were able to exhibit a potent cytotoxic activity against these cell lines. [65]
It may be helpful in Treating Cold Sores and other Viral Infections
Confidence: Low
An in vitro study showed that noncytotoxic concentrations of eucalyptus oil was able to reduce the virus titers by 57.9% for Herpes Simplex Virus-1 and 75.4% for Herpes Simplex Virus-2.
The mechanism of action was elucidated and it was found that the oil is effective before adsorption of virus into the cells. [66]
In an in vitro study carried out to analyze the antiviral effects of eucalyptus oils obtained from 8 species of Eucalyptus, it was seen that the oil of E. odorata showed maximal cytotoxicity.
E. bicostata Oil was able to inhibit viruses when used for pretreatment of cell-lines.
E. astringens oil exhibited dose-dependent antiviral activity only when incubated with virus prior to cell infection. [67]
Another in vitro study tested to show the effect of Eucalyptus oil when used as an aerosol showed that both influenza A virus and E. coli M13 phage were sensitive to the oil after 1 hour of exposure, along with significant increase in phage inactivation at all time points. [68]
Dosage
Please note, these are indicative dosages and you must consult before taking them.
For Asthma:
200 mg of eucalyptol can be taken thrice daily for 12 weeks to reduce steroid dependence and dosage of steroid medications taken by patients suffering from severe asthma. [69]
The same dose of 1,8-cineol can also be taken to relieve cough and dyspnea. [70]
For COPD:
200 mg of cineol, thrice daily for 6 months, can be given to patients suffering from COPD, as concomitant therapy, as a mucolytic agent and to reduce inflammation and improve lung function and dyspnea associated with COPD. [71]
For Bronchitis:
200mg of cineole given thrice daily for 10 days can ameliorate bronchitis and its associated symptoms such as coughing, dyspnea and thoracic pain significantly. [72]
A spray containing essential oils of Eucalyptus citriodora, Eucalyptus globulus, Mentha piperita, Origanum syriacum, and Rosmarinus officinalis can also be applied 5 times daily for 3 days, such that 4 sprayings are taken at an interval of 5 minutes each time it's applied, to relieve symptoms such as sore throat, hoarseness and cough. [73]
For Rhinosinusitis:
Two 100 mg capsules of Cineole can be given thrice daily before meals to reduce symptoms associated with rhinosinusitis such as headache on bending, the sensitivity of pressure points, nasal obstruction, rhinological secretion, redness, oedema and dryness of mucosa improved significantly. [74]
For gingivitis:
Eucalyptus oil extract chewing gum of concentrations (0.4 or 0.6%) can be chewed for five minutes, 5 times daily, for at least 12 weeks in order to treat gingivitis and eliminate plaque, inflammation and bleeding. [75]
For plaque:
Eucalyptus oil mouthwash (10ml) can be used to rinse the mouth for 5 minutes, twice daily, to reduce plaque and prevent its accumulation. [76]
Listerine mouthwash (20ml) can be used to rinse the mouth twice daily, for 30 seconds, to reduce plaque and gingivitis. [77]
For Headache:
To relieve headache, a combination of eucalyptus oil (5g), peppermint oil (10g) and ethanol (100g) can be applied using a sponge to the forehead and temples. [78]
For Osteoarthritis:
Patients suffering from joint pain related to osteoarthritis can inhale 3% (v/v) eucalyptus oil with almond oil as the carrier for 30 minutes to relieve the pain. [79]
For neuropathic pain associated with diabetes:
Aromatherapy massage with essential oils of eucalyptus, rosemary, geranium, lavender and chamomile, can be done thrice a week for 4 weeks, using the Plantar effleurage, friction, and petrissage techniques.[80]
For insect-repellent:
One ml of essential oil of Eucalyptus maculata citrodion can be used at 40% and 75% concentrations and mixed in coconut oil, can be applied topically to prevent mosquito bites. [81]
For head lice:
Head lice solution containing 11% eucalyptus oil and 1% Leptospermum petersonii can be applied thrice with an interval of a week between each application to completely eliminate lice infestation. [82]
For fungal infections:
Tinea infections can be cured using herbal preparation containing 1% eucalyptus oil, by topical application, twice daily for 3 weeks. [83]
For oral dosing:
300-600 mg supplements of eucalyptus oil can be taken for respiratory catarrh. [84]
Precautions
Adverse Effects
Eucalyptus oil must not be directly ingested as it is highly toxic and may prove to be lethal in doses between 30 and 60ml. [85]
Back pain, severe headache, gastritis, and heartburn could be a result of consuming 1,8-cineole for asthma. [86]
Nausea and diarrhoea are other side effects of ingestion of cineole. [87] Exanthema may also occur rarely. [88] It may rarely increase blood glucose levels or lead to occult blood in stools. [89]
Pregnancy, Lactation, and Children
It is likely unsafe to use eucalyptus oil during pregnancy and lactation, however, there is no sufficient evidence to prove the same. Animal studies showed no fetotoxicity due to eucalyptus oil. [90]
It may cause CNS and breathing problems in young children. During an 11-year period from 1981-1992, 109 children were admitted due to eucalyptus poisoning in Melbourne. [91]
Interactions
Many studies have shown that eucalyptus oil can induce P450 liver enzymes and thus slow down the action of these enzymes to metabolize various drugs such as amitriptyline (Elavil), haloperidol (Haldol), ondansetron (Zofran), propranolol (Inderal), theophylline (Theo-Dur, others), verapamil (Calan, Isoptin, others). [92]
Overdosage
Even very small quantities of eucalyptus oil, if ingested, may prove to be fatal. [93]
Ingesting eucalyptus oil may cause severe CNS depression, unconsciousness, ataxia, pulmonary dysfunctions, and vomiting. [94]
Death occurs in 15 minutes to 15 hours of ingestion. [95]
FAQs
Can Eucalyptus oil boost immunity?
Studies have shown that eucalyptus oil can induce macrophages and thus increase phagocytic activity and also activate the innate immune response in immunosuppressed rat models, by inducing granulocytic or monocytic systems. [96]
Can Eucalyptus oil help in improving mental health?
Aromatherapy with eucalyptus essential oil may help in improving mental clarity, calming the mind and increasing concentration. [97] It is also beneficial in treating dementia.[98]
Aromatherapy with 4 drops of eucalyptus, 4 drops of frankincense, 4 drops of rosemary and 4 drops of sandalwood is recommended for mood enhancement and stress reduction. [99]
Can Eucalyptus oil reduce fever?
It has been reported that eucalyptus oil may be an effective antipyretic, and can be applied to the skin to treat measles and scarlet fever. [100]
Summary
In a nutshell, eucalyptus essential oil has an innumerable number of health benefits and its use has been proven effective for treating respiratory disorders like asthma and bronchitis, for maintaining oral hygiene and dental health, to get rid of the pain associated with sinus, osteoarthritis and muscle pain.
Its use as an antidiabetic, antioxidant, anticancer and antiviral agent is yet to be exploited. It is also a potent antibacterial and antifungal agent. It can also be used in aromatherapy for mental clarity.
Eucalyptus oil is highly poisonous and can be lethal even at small oral doses.
Its ingestion and use should be avoided by children and pregnant women. It can interact with drugs that are metabolized by liver enzymes and even anti-diabetic drugs.
