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While research suggests there are health benefits, the FDA doesn’t monitor or regulate the purity or quality of essential oils. It’s important to talk with a healthcare professional before you begin using essential oils and be sure to research the quality of a brand’s products. Always do a patch test before trying a new essential oil.

Essential oils are extracts that give plants their fragrant aroma. These oils are widely known for their many health benefits, and they’re often applied to the skin, or used in aromatherapy and inhaled through the nose.

But essential oils aren’t just good for releasing a refreshing scent. Some may work as a natural therapy for the mind and body. Therapeutic benefits include reducing stress, anxiety, and inflammation. Some oils may even improve sleep.

Along with these benefits, some essential oils have antimicrobial properties. This means they can kill bacteria, fungi, and viral pathogens.

You might be asking yourself: How does an essential oil kill bacteria?

To put it plainly, some essential oils naturally possess antibacterial and antimicrobial compounds, and it’s these compounds that give oils the ability to fight off pathogens.

The specific compound varies depending on the particular oil, but two such compounds are aldehydes and phenols.

Aldehydes are a broad-spectrum disinfectant with the ability to sterilize and kill fungi, viruses, and bacteria. Phenols, which are compounds that act as antioxidants, have also been shown to have antibacterial properties.

The power of these compounds to destroy pathogens leads some researchers to believe that essential oils can effectively inhibit the growth of certain types of bacteria, including those that have become resistant to antibiotics in recent years.

Here’s what research has to say about the antibacterial properties in three specific essential oils: tea tree oil, lemongrass oil, and eucalyptus oil.

Tea tree oil, also known as melaleuca oil, is an essential oil that comes from the leaves of the tea tree.

It’s believed to have antiviral properties, as well as antifungal and antiseptic properties. For this reason, tea tree is often used to treat different types of skin conditions, including acne, nail fungus, and dandruff.

Similarly, research finds that properties in tea tree oil possess antibacterial activity against several harmful pathogens such as:

These pathogens can cause a variety of illnesses, including:

  • food poisoning
  • skin infections
  • pneumonia
  • stomach viruses
  • blood infections

Tea tree oil might also improve acne vulgaris, which is sometimes caused by S. aureus.

Some studies suggest that a topical application of 5 percent tea tree oil over 4 to 8 weeks improved mild to moderate acne vulgaris.

Based on this research, tea tree oil may be a reliable alternative treatment for acne.

How to use tea tree oil

The recommended dose of tea tree oil is 5 to 15 percent of topical oil applied 1 to 2 times daily. You can also apply tea tree oil to warm bathwater or use a diffuser to inhale. Don’t ingest the oil.

Not only can you apply tea tree oil topically, you can also use it as a household disinfectant.

Add 3 drops of tea tree essential oil to a spray bottle with 1 cup white vinegar and 1 cup water.

Dilute, dilute, dilute

Keep in mind that all essential oils can cause skin irritation.

Before applying any essential oil topically, be sure to dilute it with a carrier oil, such as coconut, olive, sweet almond, jojoba, or argan oil. This can help reduce the risk of skin irritation.

Never apply essential oils directly to the skin.

Lemongrass oil is another essential oil shown to have antibacterial properties.

In one study, researchers found that can be lemongrass extract was effective against Bacillus subtilis and Bacillus cereus, and it could be used to create antimicrobial drugs for treating bacterial infections.

How to use lemongrass oil

You can diffuse lemongrass oil to use as a natural air freshener in the home or inhale it to promote relaxation. Also, you might mix three or four drops of the oil with an all-purpose cleaner.

When diluted with a carrier oil, you can also apply the oil to your skin as a topical antibacterial.

First, combine 12 drops of the oil with 1 tsp. of carrier oil. Massage the oil into your skin or add it to bathwater.

Eucalyptus oil comes from the eucalyptus tree, which is native to Australia. The oil has many powerful health benefits, too, which include:

  • reducing inflammation
  • relieving asthma-related symptoms
  • improving dandruff
  • lowering stress levels

Recent studies have found that the oil of the eucalyptus plant has antimicrobial properties against the following pathogens:

  • S. aureus
  • Streptococcus pyogenes (S. pyogenes)
  • Salmonella typhi (S. typhi)
  • Shigella spp.
  • E. coli
  • P. aeruginosa

This is supported by other research, too, where scientists examined the in vitro microbial activities of eucalyptus oil against E. coli and S. aureus using agar disc diffusion and dilution broth methods.

In both cases, the plant’s oil inhibited the growth of both bacteria.

Researchers on the study concluded that eucalyptus oil could potentially be used as a natural antibiotic for several infectious diseases.

How to use eucalyptus oil

Keep in mind that eucalyptus oil is highly toxic, even in small amounts. So like other essential oils, you shouldn’t ingest it.

To use the oil, inhale it with a diffuser, or add the oil to warm bathwater.

Some people use essential oils like tea tree oil, lemongrass oil, and eucalyptus oil to treat skin conditions, reduce stress, and improve sleep. But these oils also have antibacterial properties, meaning they can potentially treat infectious diseases, too.

While some essential oils are effective against certain pathogens, they can irritate the skin when applied directly. Signs of irritation include itchiness, redness, and stinging.

Always dilute essential oils with a carrier oil first, and then apply to a patch of skin to see how it reacts.