Is Listerine a Mosquito Repellent?
Listerine is a brand of antiseptic mouthwash manufactured by Johnson & Johnson. It is meant for preventing bad breath and gingivitis, but it has developed a reputation as a mosquito killer and repellent. The reasoning behind this is tenuous at best, and no research into Listerine's effects on mosquitoes is available. The idea continues to live, however, with more success stories occasionally surfacing. Does this Spark an idea?
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Claim
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The claim that Listerine repels mosquitoes spreads from person to person via word-of-mouth or through forwarded emails or websites. Whether Listerine actually does work hasn't been studied, but enough anecdotes about using it to successfully keep mosquitoes away from doors and windows pop up that it continues to be one of the strategies mentioned to those looking for a safer way to stay bite-free. The procedure involves spraying it around door and window frames, lawns, tables and any other area you see the bugs, but the formula tends to vary. Most of the time, only Listerine is used, but at least one site suggests a mix of equal parts of Listerine and vinegar sprayed on body parts. The claims do not specify if only plain Listerine will work, or if one of the flavored varieties will, too.
Background
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This may be based -- very loosely -- on the fact that Listerine contains eucalyptol, a component of eucalyptus essential oil. Eucalyptus oil itself has been studied as a possible mosquito repellent with some success; a 1996 study, published in the "Journal of the American Mosquito Control Association," of a eucalyptus-based repellent against two Anopheles species found the substance repelled the bugs for at least six hours. The repellent, PMD, is a synthetic form of oil of lemon eucalyptus, which the Centers for Disease Control and Prevention (CDC) list as one of four repellents that can work against mosquitoes. Anahad O'Connor of "The New York Times" notes, however, that Listerine contains very low levels of eucalyptol compared to the amount of oil of lemon eucalyptus used as a repellent in the studies. Additionally, eucalyptol is a component of the oil, but it's the oil itself that's been studied; research results for one might not necessarily apply to the other.
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Money Talks
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One very true argument against using Listerine as a mosquito repellent comes from Timothy J. Gibb, of Purdue University's entomology department. If Listerine really did repel mosquitoes, Johnson & Johnson would be advertising this fact repeatedly and marketing Listerine as an effective insecticide, raking in the money. That Listerine bottles don't say anything about keeping mosquitoes away is a big hint that the mouthwash doesn't have a second use.
What to Do
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Keeping mosquitoes off your skin is possible, but stick to researched and proven remedies. The CDC notes that in addition to oil of lemon eucalyptus, three other substances can work: DEET, Picaridin and IR3535. Follow the manufacturer's directions for applying the repellents, and pay attention to any time limits listed -- you may have to reapply the repellent if you are outside for a long time.
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References
- Listerine.com: How Does Listerine Work
- Maine Hunting Today: Listerine for Mosquito Repellent?; Tom Remington; March 2008
- "Journal of the American Mosquito Control Association": Evaluation of a Eucalyptus-Based Repellent Against Anopheles Spp. in Tanzania; JK Trigg; June 1996
- MedlinePlus: Eucalyptus
- "Medical Toxicology of Natural Substances"; Donald G. Barceloux; 2008
- Tipnut: How to Prevent Mosquito Bites
