The Paul Harvey mosquito spray is a DIY yard spray made from three household ingredients: cheap blue mint mouthwash, stale beer, and Epsom salt. The recipe has circulated online for years, attributed to the late radio broadcaster Paul Harvey, though there’s no verified record of him creating or endorsing it. Regardless of its origins, it remains one of the most shared homemade mosquito remedies on gardening forums and social media.
The Recipe and How to Mix It
The standard version calls for three ingredients:
- 1 large bottle of blue mint mouthwash (any cheap store brand works)
- 3 cans or bottles (12 oz each) of stale beer (the cheapest you can find)
- 3 cups of Epsom salt
Pour the beer and mouthwash into a bucket or old saucepan, then stir in the Epsom salt until it fully dissolves. Transfer the mixture into a garden spray bottle or a hose-end sprayer. Shake well before each use.
Some versions call for equal parts of all three ingredients instead of specific measurements. The ratio doesn’t seem to be critical, since this is a folk remedy without standardized testing behind it.
Where and How to Apply It
Spray the mixture around any outdoor area where you spend time: decks, patios, porches, pool surrounds, and seating areas. If you’re camping, spray on the grass around tents. Supporters of the recipe say it won’t harm plants, flowers, or lawns, and that the Epsom salt actually acts as a mild fertilizer by adding magnesium to the soil.
Let the spray dry completely before anyone walks through or sits in the treated area. Claims about how long it lasts vary widely, with some people reporting 60 to 80 days of protection and others suggesting you’ll need to reapply roughly once a month. Rain shortens that window significantly. A couple of applications per summer is the general recommendation from people who use it regularly.
Does It Actually Work?
The honest answer: there’s no scientific evidence that this mixture provides reliable mosquito control. Each ingredient has a kernel of logic behind it, but none holds up well under scrutiny.
Mouthwash contains menthol and eucalyptol, both of which have mild insect-repelling properties. However, Snopes has evaluated the claim that mouthwash repels and kills mosquitoes and classified it as an urban myth. Spraying mouthwash may have a very short-term effect while the liquid is still wet, but it evaporates quickly and leaves no lasting barrier. Compare that to products designed specifically for mosquito control, which are formulated to persist on surfaces or skin for hours.
Epsom salt (magnesium sulfate) is often cited as the “key ingredient” by fans of the recipe, with the claim that mosquitoes hate magnesium sulfate. There’s no published research supporting this. Epsom salt does benefit plants, so it’s not harmful to spray on your lawn, but calling it a mosquito repellent is a stretch.
Stale beer appears to serve mainly as a liquid base to help dissolve the salt and distribute the mixture. Some people theorize the yeast attracts and then traps mosquitoes, but in a spray application the beer simply dries on surfaces. Beer actually attracts mosquitoes in some studies, which would work against the recipe’s purpose.
The most likely explanation for positive reports is a combination of placebo effect, natural fluctuations in mosquito populations, and the brief window when wet mouthwash on surfaces does deter insects from landing.
What Actually Repels Mosquitoes
The CDC recommends four active ingredients for mosquito repellents, all registered with the EPA: DEET, picaridin, IR3535, and oil of lemon eucalyptus (also listed as p-menthane-3,8-diol or PMD on labels). These are the only ingredients with consistent, peer-reviewed evidence behind them.
For personal repellents applied to skin, products with at least 20% DEET provide several hours of protection. Concentrations above 50% don’t add extra benefit. Picaridin at similar concentrations performs comparably without the greasy feel some people dislike about DEET. Oil of lemon eucalyptus is the strongest plant-derived option, though it tends to require more frequent reapplication.
Products with less than 10% of any active ingredient typically protect for only one to two hours. Higher concentrations last longer but aren’t “stronger” in terms of repelling power.
For yard treatment specifically, commercial mosquito barrier sprays use residual insecticides that bind to vegetation and remain active through light rain. These are a different category from the Paul Harvey mixture entirely, designed to kill mosquitoes on contact and continue working for weeks. Mosquito dunks placed in standing water target larvae before they become biting adults, addressing the problem at its source.
Is It Worth Trying?
The ingredients are cheap and nontoxic, so the Paul Harvey spray won’t harm your yard, your pets, or your family. If you enjoy the minty smell and want to try it as a supplement to proven methods, there’s no real downside beyond the cost of a few dollars in mouthwash and beer. Just don’t rely on it as your only line of defense, especially in areas where mosquitoes carry diseases like West Nile virus, Zika, or Eastern equine encephalitis. For those situations, EPA-registered repellents and professional yard treatments are worth the investment.