EcoVet Fly Repellent Formulated to be a less toxic way to control pests. Designed to be safer for the horses and the people applying the product. Using a proprietary mixture of naturally occuring fatty acids that confuses and overwhelms the insects normal directional ability, so the insect is unable to locate your horse. Product Details: Effective on many types of flies, ticks, mosquitoes and lice Long lasting product - apply 2 to 3 days Safe for sensitive skinned horses No known resistance problems No known reactions on honeybees EPA approved.