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Prevention and treatment of the common cold and its complications using essential oil synergies

With the flu season fast approaching this research paper supports the usage of several blends that we should all add to our tool kits.

Prevention and treatment of the common cold and its complications using essential oil synergies 

MAHA MAJZOUB, community pharmacist 

August 19, 2021 

Beirut, lebanon 

Prevention and treatment of the common cold and its complications using essential oil synergies 

The activity of 7 essential oils was evaluated for the prevention and treatment of common cold. The combination of Eucalyptus radiata, Ravintsara and lavender applied diluted on the skin was the most effective in increasing resistance and preventing a cold from taking hold. Another combination using Eucalyptus radiata, Scotch pine, Lavender and sweet orange proved to be effective in supporting immunity and relieving the cold symptoms including fever, and speeding up recovery. Complications from cold, such as bronchitis, otitis and sinusitis were effectively reduced when Frankincense, Tea tree and Eucalyptus radiata were used; whether applied on the skin or inhaled using steam inhalation or a diffuser. These results are due to the immunity boosting, antiviral, antibacterial, anti-inflammatory and bronchodilating properties of the major constituents of the studied essential oils. It is important to note that this study was conducted during the 2016-2018 cold seasons, before the emergence of COVID19 pandemic. 


Essential oils are powerful aromatic substances produced by aromatic plants (1). They have been traditionally used for respiratory tract infections (2), and are nowadays regaining interest as natural ethical medicines for colds (3). 

The common cold is an acute, self-limiting viral infection of the upper respiratory tract involving the nose, sinuses, pharynx and larynx. It is often complicated by congestive otitis, sinusitis, bronchitis or even in some cases a bacterial superinfection (4). 

As a community pharmacist, I know that conventional medicines can only address the cold symptomatically. They do not have any immune supportive effect, nor any antiviral or anti-bacterial properties. Whether treated or not, the common cold often led to the complications mentioned above. This is why my interest in medicinal plants increased and I started recommending them as a natural alternative to synthetic drugs, particularly against microbial agents with the ever-growing problem of antibiotic resistance. 


Essential oils 

Eucalyptus (Eucalyptus radiata), sweet orange (Citrus aurantium), lavender (Lavandula angustifolia), Ravintsara (Cinnamomum camphora), frankincense (Boswellia carterii), tea tree (Melaleuca alternifolia), scotch pine (Pinus sylvestris). 

Essential oils were imported from the Australian Warehouse of Oils. All the oils were stored at room temperature in the dark. All essential oils were subjected to chromatography analysis for quality control. 

Essential oils major constituents 

Essential oils used are listed in Table 1, together with their respective major chemical components. The same lots of each oil were used throughout the experiments. The high quality of these chemicals was confirmed by gas chromatographic (GC) analysis. 

Table 1. Chemical components Essential oils used 

Main chemical components 

Eucalyptus (Eucalyptus radiata) 

1.8-cineole 73% 

α-terpineol 11% 

Sweet orange (Citrus aurantium) 

Limonene 94% 

Lavender (Lavandula angustifolia) 

linalyl acetate 46.98% 

linalool 27.43% 

Ravintsara (Cinnamomum camphora) 

1,8-cineole 56.55% 

α-terpineol 7.72% 

Frankincense (Boswellia carterii) 

α-pinene 44.88% 

β-myrcene 7.73% 

d-limonene 10.19% 

Tea tree (Melaleuca alternifolia) 

terpinen-4-ol 41% 

γ-terpinene 21.32% 

α-terpinene 10.33% 

Scotch pine (Pinus sylvestris) 

α-pinene 44% 

β-pinene 21% 

Limonene 8% 

Carrier oils
We used a mix of two carrier oils: sesame oil for its warming effect and sweet almond oil.
Blends and dilutions
Three skin applied synergies were prepared. For each topical blend the dilution of essential oils was 2%. Lavender was added to each of the three blends as skin protective at the dilution of 1%. A fourth diffuser blend of pure undiluted essential oils was also prepared.
Table 2. The Immunity Booster Blend 30ml

Essential oilNumber of drops
Eucalyptus radiata6

Table 3. The Cold and Flu Blend 30 ml

Essential oilNumber of drops
Eucalyptus radiata5
Scotch pine5
Sweet orange2

Table 4. The Clear Recovery Blend 30ml

Essential oilNumber of drops
Eucalyptus radiata4
Tea tree4

Table 5. The Breathe Easy diffuser blend 6ml

Essential oilVolume in ml
Eucalyptus radiata3
Scotch pine3

Table 6. Therapeutic indications of each blend.

Immunity boosterTo increase the body’s natural defenses against viral and bacterial infections
Cold and FluTo ease the cold and flu symptoms such as congestion, sore throat, cough, headache
Clear RecoveryTo relieve chesty cough, prevent bronchitis, prevent otitis, prevent sinusitis in predisposed patients
Breathe easyTo ease cough and shortness of breath; airborne antimicrobial

This study included a cohort from random individuals visiting the community pharmacy.
The cohort was randomized in term of inclusion criteria including: sex, age, health and socioeconomic status. Age range was 15-50 years. Such diversity and randomization truly mirror the population we live in today.
Table 7. Number of volunteers for each blend.

Immunity booster54
Cold and Flu66
Clear Recovery47
Breathe easy51

Methods of application
The Immunity Booster was used at the start of the cold season in the fall daily for two weeks. Then again during spring for two weeks. Five drops were applied on each side of the neck around the lymph nodes. The excess was taken up around the ears and down to the chest. Anything left on the fingers was deeply inhaled.
The Cold and Flu Blend was used at the start of cold signs, applied (on the skin) on the throat, around the ear, on the back of neck and on the chest. Two to three drops on each site, up to three times daily. Anything left on the fingers was deeply inhaled.
The Clear Recovery Blend was used twice daily, morning and evening for those who started any signs of chesty cough or for those who usually develop recurrent bronchitis and/or otitis after a cold episode. Three to five drops to be rubbed on chest and/or around the ears depending on the patient’s concern. Anything left on the fingers was deeply inhaled. 
The Breathe Easy Blend is a diffuser blend, used as needed daily to relieve congestion and /or cough. We recommended using it at night as 10-15 drops in a diffuser in an aerated bedroom.  
Individuals were asked to use the Immunity Booster blend for two weeks and the other blends for one week before assessment.
Special precautions
The Cold and Flu blend contains Citrus aurantium (sweet orange), an essential oil that can be photosensitizing according to Ao, Yoko, et al. (5). Although present at a low concentration in the blend, we recommended staying away from sunlight while using it or applying it on covered skin.


The tables below show, for each blend, the different criteria evaluated according to a 5-point rating scale. Each individual in the study was asked to rate the blend for each criterion, 1 being no improvement at all and 5 a drastic improvement or full recovery. Below each rating point is the number of individuals who voted for this point.
Table 8.1. Immunity Booster Blend

Temperature and weather-related illness057834
Cold epidemics24101127
Seasonal fatigue039933
Back to school/work illness5231628
Travel-related illness2092320

Table 8.2. Cold and Flu Blend

Sore throat7617297
Cold/flu duration50112723

Table 8.3. Clear Recovery Blend

Chesty cough2161226
Bronchitis prevention023933
Congestive otitis prevention14141612
Bronchitis treatment43111514
Congestive otitis treatment3492110
Illness duration20121617

Table 8.4. Breathe Easy blend

Chesty cough03101820
Shortness of breath4281918
Nasal congestion31102710




  1. Immunity Booster Blend Results

The volunteers who used daily the Immunity Booster blend experienced a significant resistance to viral epidemics, specially with the change of seasons or when caring for sick patients or when feeling run down and under stress. Performance and immunity can be increased by essential oils, through the increase of lymphocyte transformation and leucocyte phagocytosis rates, as well the levels of immunoglobulins in blood (6). Cinnamomum camphora (Ravintsara) essential oil is empirically known for its anti-viral and immunostimulating properties (7). It has also shown anti-inflammatory actions which  may be due to the modulation of cytokine, NO and PGE2 production and oxidative stress (8). The major component of Eucalyptus oil (1,8 cineole) have immune-stimulatory, anti-inflammatory and anti-oxidant effects (36). Of the white blood cells stimulated, monocytes and macrophages are most affected with an increase in the phagocytic activity. This explains the increased resistance and the less vulnerability to airborne illnesses.
On the other hand, stress plays a huge role in decreasing immunity. Physiological stress has been linked to an increase in the stress hormone cortisol levels and a decrease in total T lymphocytes (10). Psychosocial stress was also shown to deplete mucosal immunity against viral and bacterial invasions in children, leading to recurrent upper respiratory tract infections (11). Lavender (Lavandula angustifolia) essential oil has sedative and healing effects on the nervous system, due to its high content in Linalool and Linalyl acetate. A study conducted by Toda 2008, showed a significant reduction in salivary stress markers after arithmetic test in student exposed to Lavender essential oil during the resting period (12). This explains the less vulnerability to illnesses that accompany back to school and travel related stress.
Furthermore, Cinnamomum camphora (Ravintsara) essential oil is an excellent nerve tonic (13), which makes it excellent to fight fall and winter lack of energy and fatigue. 

  1. Cold and Flu Blend Results

As mentioned in the paragraph above, Eucalyptus has immune-stimulatory, anti-inflammatory and anti-oxidant effects. One of its major constituents, alpha terpineol, exert a strong antiviral activity (14), supporting the immune system during a viral cold infection for a faster recovery. Another constituent,1,8 cineole, has expectorant and mucolytic effects (15,16), contributing to the cough relieving effects of the blend.
A study conducted by Arora showed that oils rich in alpha and beta Pinene such as Pinus Sylvestris (Scotch pine) builds up resistance to colds and coughs and reduces cold symptoms: fatigue, sore throat, sore muscles and runny nose (17).
Citrus aurantium (Sweet orange) essential oil relieves the discomfort of bronchitis and flu (18). Interestingly, it was also found to reduce stress while increasing cheerfulness and vigorousness, easing the fatigue and low mood that usually accompany colds and flu (19). This is thought to be due to its high content of the monoterpenes d-limonene and β-myrcene.

  1. Clear Recovery Blend

The main component of Eucalyptus, 1,8-cineole has mucolytic, bronchodilating and anti-inflammatory properties. Fisher and Dethlefsen studied the efficacy of Cineole in patients suffering from acute bronchitis. They found that after four days of treatment with Cineole, there was significant improvements of the bronchitis-sum-score, with a significant reduction in cough frequency (20). 
Frankincense exerts an anti-inflammatory effect through the down regulation of pro-inflammatory cytokines (21). Furthermore, alpha-pinene linalool and 1-octanol contribute to the topical anti-inflammatory activities of frankincense via the inhibition of COX-2, according to Xiao-Jun Li et al, 2016 (22). In a study by Gupta et al 1998, the improvement of chronic bronchial asthma was obvious in 70% of patients after a 6-week treatment with Boswellia serrata (24). This explains why Frankincense has been traditionally used to treat cough, catarrh, bronchitis and asthma (23).
A study by A.H Gilani et al 2000, confirmed the antispasmodic effect of Lavandula angustifolia on smooth muscles through calcium channel blockade. This explains the soothing effect of lavender on the tracheal smooth muscles, reducing spasmodic cough (25).
Melaleuca alternifolia (tea tree) essential oil has strong antibacterial properties, inducing lysis of microorganisms during their exponential phase of growth (26). Its main component, terpinen-4-ol, was proved active against a range of pathogens in a study by Carson 1995 (27). Another study showed a high susceptibility of gram-positive bacteria to tea tree, making it ideal in the prevention of the superinfection with bacterial pathogens like Streptococcus aureus after the flu (28). The monoterpene gamma-terpinene manifests an anti-inflammatory activity by modulating cytokine production and inflammatory cell migration into the lung tissue; explaining its beneficial effect on allergic cough and other lung allergic complications (29).
The synergistic effect of these four essential oils (Eucalyptus, Frankincense, Tea tree and lavender) is completed by the use of Nigella sativa (blackseed oil) as carrier oil: a study suggests possible prophylactic effects of Nigella sativa seed extract in asthmatic patients (31).

  1. Breathe easy blend
The inhalation therapy of essential is medicinally used to treat chronic and acute respiratory conditions, maintaining the ventilation and drainage of the sinuses (30). A study conducted by Shigeharu et al in 2001 evaluated the activity of essential oils in respiratory infections though gaseous contact. The results showed an impressive activity against Streptococcus and H. influenzae, two of the bacteria the most involved in upper and lower respiratory tract infections (32).
Alpha pinene, the major component in Pinus Sylvestris (pine) essential oil, can ameliorate allergic symptoms in a mice allergic rhinitis model (33).
Kehrl et al, 2009 evaluated the use of Cineole in congestive rhinosinusitis. Patients treated with Cineole, the major component in Eucalyptus, showed significant amelioration of tension headache, nasal obstruction and rhinological secretions (34).
One of the components of Eucalyptus, alpha-terpineol, was proved to have anti-asthmatic, anti-tussive and expectorant effect with a good safety margin in allergic guinea pigs models (35).
The results of a study conducted by Hirota et al, 2010 suggest that limonene, one of the components in Pine essential oil, may have anti-inflammatory efficacy through the inhibition of cytokines production and eosinophils migration, contributing to the positive effect on shortness of breath and chesty cough.

The results are promising and can be utilized in multifactorial -stress related, inflammatory or infectious – ailments. These most awe-spiring over the counter natural remedies have the advantages of being effective all while being free of the side effects that come with prescription drugs when used properly. Used as soon as possible at the first signs of a cold, they can help speed up recovery and prevent bacterial superinfection; thus, sparing the patient an unnecessary antibiotic course. With the spread of multidrug resistant bacteria, essential oils form a new horizon in combating bacterial antibiotic resistance.  
The efficacy of essential oils in cold and flu treatment vs conventional over the counter drugs comes with the interesting difference that, unlike drugs, essential oils can support immunity instead of stressing the body’s detoxifying systems, leading to a stronger a more resistant body. Whether faced by infections, fatigue, stress or auto immune diseases, the body’s resilience seems much stronger when least exposed to chemical treatments and more to natural remedies.

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