This product is designed to be used added to feed to help repel midges, mites, ticks and all biting insects/parasites. Effective against mites in dogs and horses. It takes about 1 week to take effect in horses. It is not a topical application. Once it is in the system it can be reduced to a maintenance dose. Repel-It is 100% herbal like all our other products and does not contain any chemical insecticides.