Remember that it's not just your horse you're exposing to fly spray. When you mist your horse with chemical fly spray you expose not only your horse, but yourself, other riders, and the environment to dangerous chemicals. Even though the pesticides in these products are considered "safe" for a 1000 pound horse, the creatures that share your barn space are also exposed and many of them are smaller and more fragile than our equine friends. Residue from fly spray (and any chemical products you use on your horse) slowly make their way into soil, groundwater, and streams. You're not just spraying your horse. You're spraying our world. And the more we spray we use, the more resistant the target bugs become to insecticide. Worse yet, using poison has the very unfortunate consequence of killing not only the flies but the natural predators of the flies. Sometimes bugs get so bad we feel we have no choice but to use the serious spray. But don't make it a habit. Environmentally friendly alternatives are available. And they work if you maintain consistency.