Insect repellents that use chemicals such as DEET provide proven protection from bug bites. If you're looking for a more natural alternative to keep insects away, however, you may find just what you're looking for in your bathroom medicine cabinet.
Listerine is an antibacterial mouthwash meant to prevent halitosis, more commonly known as bad breath. The active ingredients in Listerine are menthol, thymol, methyl salicylate and eucalyptol. According to the product's marketing claims, the mouthwash is effective in killing oral bacteria, reducing plaque build-up and preventing gingivitis. In addition, various websites claim Listerine also is effective as an insect repellent. The primary reason for this is the presence of eucalyptol, which is derived from eucalyptis oil. Eucalyptol, often mixed with lemon oil, is used in some brands of chemical-free insect repellents. Insects also are repelled by menthol and thymol.
According to The Daily Puppy website, the original yellow-coloured Listerine works better than other varieties. The best way to keep your back yard or other outdoor area free of insects is to fill a large spray bottle with Listerine and spray it liberally on plants. For added effectiveness, the Pantry Spa website recommends first spraying the area with a mixture of water and garlic powder and then spraying with a half-and-half mix of Listerine and white vinegar.
If Listerine is not available or if you'd like to augment your insect protection with other nontoxic household products that repel insects, one alternative is to rub Vicks VapoRub on yourself. The powerful menthol scent is abhorrent to insects. Another way to repel insects is to take ordinary dryer sheets that you would typically use for drying laundry and hang them out of the pockets and waistband of your trousers.
An Urban Legend?
Of course, it's possible that Listerine's effectiveness is, at best, overstated and, at worst, an urban myth. According to urban-legend website Snopes, Listerine may indeed have an insect-repelling effect, but its effects are short term: "[Listerine] may kill some mosquitoes on which it is directly sprayed, but it won't serve to keep knocking mosquitoes dead for hours and hours afterward." As Snopes indicates, Listerine's effectiveness is limited, an nowhere near as powerful as commercial insect repellents, especially those that contain DEET.