When you read the words ‘essential oils,’ the first image that comes to mind is of aromatherapy or massage in some luxurious spa. However, there is much more to essential oils than spa therapies and massages.

Essential oils have been used in folk medicine for their ability to heal and fight off infections. These oils contain a variety of secondary metabolites that inhibit or slow down bacteria, yeasts, and molds.

Antibiotics, the traditional treatment for bacterial infection, can cause many side effects. Moreover, overuse of antibiotics has led to the creation of drug-resistant bacteria.

Hence, researchers are now opting for essential oils as a low-cost solution for treating bacterial infections.

While all essential oils can kill bacteria, some have a stronger anti-bacterial effect than the others. Here are some of the best antibacterial essential oils –

1. Tea tree oil (Melaleuca alternifolia)

Tea tree essential oil, also known as melaleuca oil, comes from the leaves of the tea tree plant which is native to Australia. It has been used for hundreds of years by the aboriginal communities for its antiseptic and anti-inflammatory properties.

This oil first gained prominence when Arthur Penford published a series of papers on its antiseptic properties. Since then there have many numerous studies on its beneficial effects.

In 2004, a lab study showed that tea tree oil could kill methicillin-resistant Staphylococcus aureus. In 2013 researchers replicated the same effect in humans.

During the study, ten patients with wounds infected with Staphylococcus aureus were treated either conventionally or with tea tree oil. The results demonstrated that the healing time decreased in all but one participants that were treated with tea tree oil (1).

According to a 2016 study from India, tea tree oil and eucalyptus oil are effective against E. coli and staph infections (2).

Ways to use

  • You can use this oil in a diffuser or nebulizer to ward off chest congestion and other symptoms of cold and flu.
  • Add two drops of tea tree oil in your wound ointment cream and use as directed.

2. Oregano oil (Origanum vulgare)

Oregano essential oil is taken from the leaves of the oregano plant. It has been used traditionally to treat cough, colds, flu, and bronchitis for hundreds of years. The antiviral, anti-inflammatory and antibacterial properties of oregano oil help it in fighting various infections.

Oregano oil contains thymol and carvacrol, which inhibits the growth of bacteria like Staphylococcus aureus and Klebsiella pneumoniae that are responsible for respiratory infections (3).

A 2012 study investigated the antibacterial activity of oregano oil against Escherichia coli and Pseudomonas aeruginosa. The results showed that oregano oil inhibited the growth of both strains of bacteria (4).

Oregano oil is considered a broad-spectrum antibacterial as it kills both gram-positive and gram-negative bacteria. In fact, oregano oil is also effective against antibiotic-resistant bacteria (5, 6).

Ways to use

  • For a sinus infection, add a few drops of oregano oil to steaming water and inhale the steam.
  • For toe or foot fungus, add a few drops to a tub of water and soak your feet in it.

3. Thyme oil (Thymus vulgaris)

Thyme oil is steam distilled from the leaves and the flowering tops of the Thymus vulgaris plant, a member of the mint family. This oil is known for its antibacterial, antiseptic, antifungal, and diuretic properties.

A study from the University of Tennessee evaluated the effect of thyme oil against bacteria in milk and salmonella. The results showed that its nanoemulsions are an excellent option for protecting our body from harmful bacteria by using it as an antimicrobial preservative for food (7).

The expectorant and antispasmodic properties of thyme oil treat respiratory illnesses. It can reduce phlegm, fight bacteria and viruses and reduce spasms.

It also helps in curing bacterial infections like B-Colitis, renal colic, and infections in the genitals, intestines, urethra and the respiratory system.

Ways to use

  • Diffuse a few drops of this essential oil throughout your home.
  • Add a few drops of thyme essential oil to a bowl of boiling water and inhale the steam.

4. Cinnamon oil (Cinnamomum verum)

The cinnamon essential oil is extracted from the bark of the trees that belong to the Cinnamomum species. Cinnamaldehyde, eugenol, and linalool make up about 82.5 percent of the cinnamon oil composition.

These active components provide antibacterial, antioxidant, anti-inflammatory, anti-diabetic and anticancer properties to cinnamon oil.

During a 2011 study, several extracts of cinnamon were tested against MRSA by in vitro methods. The results showed that the extracts of cinnamon showed strong in-vitro antibacterial activity, which can be valuable for the treatment of infection (8).

In 2014, a study was done to determine the antibacterial activity of cinnamon oil against gram-positive and gram-negative isolates belonging to Staphylococcus, Enterococcus, Enterobacter, and Acinetobacter genera.

The investigations showed that cinnamon bark oil has inhibiting activity against all strains. So, cinnamon oil can be used as an alternative antibacterial agent in cosmetics, toiletries, and disinfectants (9).

According to a study published in the Journal of Contemporary Dental Practice showed that cinnamon oil is effective against planktonic and biofilm E. faecalis and it was cytocompatible to L929 fibroblasts. So, it can be used as an antimicrobial agent in root canal treatment (10).

Ways to use

  • Put one drop on your toothbrush before adding toothpaste.
  • Diffuse a few drops in a diffuser to kill off air-borne bacteria.

5. Grapefruit essential oil (Citrus Paradisi. L)

Grapefruit essential oil is derived by cold pressing the peels of the grapefruit. This essential oil has potent antibacterial and antimicrobial effects.

According to studies, it has a broad spectrum of antimicrobial activities against Staphylococcus aureus, Staphylococcus epidermis, Enterococcus faecalis, Escherichia coli, Salmonella typhimurium, Serratia marcescens and Proteus vulgaris (11, 12).

Grapefruit oil can prevent infection caused by H pylori, which can lead to stomach ulcers. In a study that examined the effects of 60 essential oils against H. pylori, the researchers found that white grapefruit essential oil has antibiotic effects (13).

Grapefruit essential oil also contains antimicrobial properties that help treat and prevent infection in wounds and cuts. It supports endocrine function and encourages the production of gastric juices to aid digestion.

Ways to use

  • Add one drop of this oil to your water and drink it.
  • Mix it with a carrier oil and apply it to prevent wounds from getting infected.
  • Avoid sunlight after applying grapefruit oil topically.

6. Clove essential oil (Syzygium aromaticum)

Clove oil is steam distilled from the flowering buds of the clove tree. Clove essential oil contains 85 percent eugenol, a phenol that contributes to the rich aroma and therapeutic properties of this oil.

This oil is used as an antiseptic in oral infection as it inhibits gram-negative and gram-positive bacteria as well as yeast.

A 2012 study tested the antimicrobial activity of clove oil against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The results showed that Escherichia coli were more sensitive even though clove oil exerted a satisfactory action in all three cases (14).

During another study 21 essential oils were tested against six bacterial species. The results showed that 19 of the 21 oils, including clove oil, showed significant antibacterial activity against one or more strains (15). 

Ways to use

  • For tooth pain add one drop of clove oil to a cotton ball and press it on the affected tooth.
  • Inhale this oil through steam inhalation to treat cough, cold or asthma.

7. Lemongrass essential oil (Cymbopogon citratus)

Lemongrass essential oil is taken from the dried leaves of the lemongrass plant. The essential oil contains citral and limonene which stifle the growth of bacteria and fungi.

It inhibits bacterial growth both internally and externally which helps in treating bacterial infections, skin conditions, body odor, and food poisoning.

According to research published in the Asian Pacific Journal of  Tropical medicine, lemongrass essential oil is effective against many drug-resistant organisms, even at low concentrations (16).

Another study tested the sensitivity of five strains of Staphylococcus aureus to five essential oils. The results showed that in comparison to other essential oils, lemongrass exhibited the most effective antimicrobial and anti-biofilm activity (17).

Ways to use

  • You can diffuse this oil through your home using a diffuser or vaporizer.
  • Dilute it in the ratio of 1:1 with coconut oil and apply it on your skin.
  • Add one drop to your water or smoothie before consuming.

Side effects and precautions

Most essential oils are safe to use and do not have any side effects when they are used correctly. However, in some cases, synthetic ingredients are added to these oils. So always choose pure organic essential oils from a reputable source.

Essential oils are highly concentrated extracts, so they must always be diluted and consumed in the correct dosage. Consult with a holistic doctor or an essential oil expert before you take any of these oils.

You must always dilute essential oils with carrier oils before topical application to avoid damage to the skin.

Some essential oils can cause drug interactions, so consult with your healthcare provider before using essential oils if you are taking any medications.

Final thoughts

Essential oils have been used to treat infections, treat skin conditions and fight bacteria for years. In the modern world, where antibiotic resistance is on the rise, these essential oils can be used to treat various infections.

Tea tree oil, oregano oil, thyme oil, cinnamon oil, grapefruit oil, clove oil, and lemongrass oil have strong antibacterial properties that can fight infections like Staphylococcus aureus and Escherichia coli.

These essential oils can be used aromatically, topically and internally to fight off various bacterial infections. However, one must use these oils correctly to avoid any side effects.

Tea tree oil, oregano oil, thyme oil, cinnamon oil, grapefruit oil, clove oil, and lemongrass oil have strong antibacterial properties.