The idea that Listerine could stop mosquitoes seemed like another urban rumor when it first popped up in the 2000s. However, the active ingredient in Listerine is Eucalyptol. It is a derivative of Eucalyptus oil, which mosquitoes hate. While no scientific study has confirmed this as of 2011, the mosquitoes do seem to detect the oil in the Listerine scent. They will avoid the scent for a while. Spraying with Listerine isn't a permanent solution to a mosquito problem, but it may deter them long enough for a person to enjoy being outside.
How to Repel Mosquitoes with Listerine
Things You'll Need
Pour as much Listerine as you're willing to lose into half of a clean spray bottle. Fill the rest of it with water.
Generously spray your arms and the area you want to be mosquito free. Spray surfaces like tables and chairs.
Spray an outdoor area every hour. The Listerine will quickly evaporate and the mosquitoes will return.