The smell of oil of citronella repels blood-feeding mosquitoes, ticks, and fleas. The oil is extracted from Cymbopogon nardus and Cymbopogon winterianus grasses, thus is all-natural. As a non-toxic substance, many people prefer citronella to other chemical repellants such as DEET.

Citronella oil appears in many products designed to protect humans, pets, and open-air spaces from the public health risks posed by mosquitoes and ticks. A concerned person could use a spritz on their clothing, lotion or soap on their skin, treated collars on their pets, and candles or pellet bags surrounding their picnic. Innovative retailers have even created wristbands, personal wipes, and sunblock spray. Citronella is totally harmless to most people, although occasionally a mild irritation might develop from an allergic reaction.

Most of the insect repellants whose only active ingredient is citronella are not regulated by the EPA (Environmental Protection Agency) because they are not technically pesticides. The smell of citronella is unpleasant to insects, but it doesn't harm or alter them in any way. A lotion with 10% concentration of citronella oil has been shown to deter insects for up to an hour. This natural alternative to DEET, while not as long lasting, does not come with government warnings. It's often combined with other natural insect repellants, such as catnip, cedar oil, mint, or rubbing alcohol.

Mosquitoes and ticks harbor many highly dangerous diseases, such as encephalitis and Lyme's Disease. The contagion passes into our bloodstream when mosquito saliva acts as a carrier at the bite sight. Mosquito populations are best controlled by preventative measures such as eliminating breeding locations. But seasonal spikes in population, or dawn/dusk exposure, make humans especially susceptible to bites. Pets roaming in brush off trails might pick up ticks. That's why it is important to remain vigilant in the prevention agains infection.

Incidentally, growing the grass from which citronella is derived will not protect your garden from insects; it is not fragrant enough, although you might detect a faint lemon smell. Citronella oil might be found as a rare flavoring in certain dishes, adding a peculiar lemony spice. The two grass varieties are native to Java and Ceylon.