Flys-Off is made for dogs and horses. It protects wounds and sores by killing or repelling flies. The ointment is applied directly to the wound or abrasion. Flys-Off topical insecticide repels flies from wounds and open sores. The active ingredients include piperonyl butoxide, pyrethrins I and II, and di-n-propyl isocinchomeronate. Piperonyl butoxide is used in conjunction with pyrethrins for their synergistic pesticidal properties.