Three Essential Oils Exhibit Antibacterial Properties
In the last 20 years, essential oil use in the United States has become commonplace. Essential oils, which have traditionally been used to treat everything from the common cold to respiratory tract infections, are now being used in conjunction with allopathic medical treatments to treat acute and chronic bronchitis, as well as acute sinusitis. [1,2] Studies have shown that inhaling essential oil vapor can help as a respiratory expectorant , help with the ‘ventilation and drainage of sinus’  and help reduce the effects of asthma.
Three oils really stand out when discussing the medicinal antibacterial effects of essential oils, and those are: Cinnamon, Lemongrass and Thyme. For the purposes of this discussion, we will only consider the benefits of these oils while diffused, not when taken topically or internally. And lastly, I realize of course that there are thousands of oils that could be considered, I have chosen to highlight oils that are familiar and readily available in the US.
First let’s discuss: Cinnamon- (Cinnamomum verum) Cinnamon essential oil is steam distilled from the dried inner bark of the cinnamon bush. This evergreen bush is a member of the Laurel family, and is native to Sri Lanka, India and Myanmar.  Cinnamon’s main constituents are cinnamaldehyde, cinnamyl acetate, and eugenol and it has an sweet, spicy and woody scent. Lemongrass- (Cymbopogon citratus) Lemongrass essential oil is steam distilled from Lemongrass, and is native to Asia, Africa and Australia.  Lemongrass main constituents are Geranial, neral, Geraniol and it has a citrus and herbaceous scent. Finally we have Thyme- (Thymus vulgaris) Thyme essential oil is steam distilled from the low growing woody herb which is a member of the mint family. Native to Eurasia but is cultivated around the world, thyme is used heavily in cooking. The main constituents of Thyme are carvacrol and thymol. 
In numerous studies, these three oils were evaluated against, Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus. [9, 10, 11] and the proved effective with a minimal inhibitory dose (MID) or minimal inhibitory concentrations (MIC). Studies also found that essential oils with a high vapor rate concentration were the most effective against the H. influenzae, S. pneumoniae, S. pyogenes and S. aureus. So, when you walk into a friends home or your next doctor’s appointment and you encounter a diffuser filling the office with the sweet woodsy smell of cinnamon, or the citrus smell of lemongrass, you will know that it isn’t simply because it smells lovely, but it can also help keep you safe and healthy.