We looked at the hard evidence to see if eucalyptus or its derivatives were effective as a natural mosquito repellent and/or mosquito killer.
Summary of Scientific Research
In general terms, eucalyptus is a genus of over 700 plants that are often fibrous with oily leaves. When discussing mosquito repellent properties, “eucalyptus” is often used as shorthand for one of two different types of plants, one which falls into the eucalyptus genus and one that does not. Both plants – Eucalyptus globulus (southern blue gum) and Corymbia citriodora (lemon eucalyptus) – are used for sourcing eucalyptus oil and have been studied for their insect repellent qualities accordingly.
First, Eucalyptus globulus oil (often simply called eucalyptus oil) is sourced from the southern blue gum tree through a steaming process. Back in 1991, this oil was scientifically tested and was found to be moderately effective at repelling ants in a laboratory environment (1). Further field tests in Guinea have shown around a 72% efficiency at blocking a certain species of mosquito over a two hour time period (2).
Similarly, Corymbia citriodora oil (commonly known as lemon eucalyptus oil) has received extensive testing that has led it to it being included in some commercially available DEET-alternative bug sprays. One field study in Bolivia found a dermal application of this oil to be ~97% effective in blocking mosquitos for a full four hours. Two other laboratory studies found this oil to even be 100% effective in deterring two well-known disease-carrying mosquito species for up to 2 hours and 12 hours, respectively (2).
In terms of active ingredients, standard eucalyptus oil makes use of a compound called PMD in order to mask the user’s natural mosquito-attracting scent. While lemon eucalyptus oil also includes some PMD, it also benefits from the natural inclusion of citronella within its botanical makeup (3).
Generally speaking, the majority of natural mosquito repellants have produced mixed results when it comes to both scientific and first-hand testing. However, lemon eucalyptus oil, in particular, has provided reliable results when it comes to preventing mosquitoes from biting, regardless of application style. As such, it can certainly be considered one of the most effective natural mosquito repellant options available.
Along the same lines, lemon eucalyptus oil holds some of the best potential for broad use as a DEET alternative due to its present availability in a consumer-friendly product. Several major brands have produced lemon eucalyptus oil sprays that are advertised for their comparative effectiveness, their pleasant scent, and their lack of greasy residue. This certainly makes lemon eucalyptus oil a valuable option for folks who do not have time to create or grow their own natural mosquito repellant.
Forms of Eucalyptus and Where to Get it
- Eucalyptus trees – Both types of eucalyptus oil derive from the leaves and bark of their respective trees, making them difficult to source independently without an established grove in your area. However, certain types of eucalyptus oil-producing trees can be found natively in Australia.
- Consumer Sprays – Most often, eucalyptus oil is converted into a spray-type product in order to maximize efficiency over the entirety of a user’s body. These sprays are usually marketed based upon their sweet, lemony scents, as well as their lack of harsh chemicals that irritate some individual’s sensitive skin. These sprays are widely available both online and at local outdoor gear stores.
- Homemade Spray – As an alternative to commercial sprays, those wishing to try eucalyptus oil on their own can make their own spray at home. These sprays are versatile and can include a desired concentration of active ingredients based upon their volume of solvent. To make such a spray, try out the following steps:
- Combine 2 tablespoons of either vodka or witch hazel with 2 tablespoons grapeseed oil, jojoba oil, almond oil, or olive oil.
- Add in 50 – 100 drops of concentrated eucalyptus oil (available online)
3 – Consumer Reports. Do ‘Natural’ Insect Repellents Work?. Consumer Reports. May 20 2019
Other Plants & Herbs as Mosquito Repellents
Checkout our analysis of other plants & herbs as natural mosquito repellents: