How Well Does Oil of Lemon Eucalyptus Work in Bug Sprays?

Let’s start with what OLE isn’t: It’s not an essential oil, despite a name that would understandably make you think otherwise. Instead, it’s refined from oil extracted from the Australian plant Corymbia citriodora, aka lemon-scented gum. (That’s another misleading aspect of the name oil of lemon eucalyptus: Corymbia citriodora used to be considered a member of the Eucalyptus genus, but it isn’t anymore.)

The main component of oil of lemon eucalyptus that gives it its repellency to bugs is a chemical called p-Menthane-3,8-diol, or PMD. PMD came to the attention of U.S. scientists in the 1990s after they learned that a Chinese insect repellent called Quwenling was performing better than many other plant-based repellents. Quwenling’s main component is PMD.

CR tests insect repellents by having volunteers put their repellent-covered arms into cages full of disease-free mosquitoes and seeing how long it takes for them to start biting. Our current ratings include eight products we’ve tested that have 30 percent oil of lemon eucalyptus. Of those, four performed well enough to earn our recommendation—which means they provided at least 5 hours of protection against mosquito bites and, in some cases, as much as 7 hours. (Other, lower-ranked OLE repellents tend to provide around 3 or 4 hours of protection.)

The safety of oil of lemon eucalyptus isn’t as well studied as, for instance, deet. But evidence suggests that it poses little risk when used according to the label. For one thing, the Environmental Protection Agency classifies oil of lemon eucalyptus as a biopesticide, which means that it’s a naturally occurring substance considered to be a lower risk than more conventional pesticides.

The main risk of oil of lemon eucalyptus is that it could be harmful to your eyes, so take care to avoid spraying it in such a way that it might get in your eyes. As always, when applying repellent to your face, you should spray it into your hands first and rub it onto your face.

The other caveat: Oil of lemon eucalyptus shouldn’t be used on young children. “It’s not registered for children under 3 years of age,” says Mustapha Debboun, PhD, a medical and veterinary entomologist and general manager of the Delta Mosquito and Vector Control District in Visalia, Calif. oil of lemon eucalyptus’ safety hasn’t been well studied in this group.

Here are a few of CR’s recommended products containing 30 percent oil of lemon eucalyptus.