Mighty Mint Rodent Repellent Peppermint Spray is made with a high-strength concentration of peppermint essential oil - a proven effective natural deterrent for rodents. This Northwest peppermint, in particular, has a smell that is pleasant to humans, but irritating to unwanted pests. Just a few sprays every few days is enough to keep an area protected from rodents. For best results, use it as a preventative measure before rodents have nested. Don't waste time with partially effective solutions - Mighty Mint is one of the strongest essential oil rodent sprays available.