Vet's Best Mosquito Repellent Spray for Dogs & Cats Vet's Best Mosquito Repellent repels mosquitoes without the use of DEET. Uses plant-based ingredients including certified natural essential oils like Lemongrass Oil and Geraniol (from Citronella plants). Proven effective and manufactured in the USA. Can be used on dogs and cats 12 weeks or older. Also great forthe whole family. Can be reapplied every 2 hours as needed.