. . . "Vinegar will change the PH of the body to help repel insects of all types so mixing with it instead of water just makes sense to me.I find this is working for all my horses (3) very well all day long.I even dilute it further for my light colored palomino, as he does not attract bugs as much as my black horse or my chesnut.Highly recommend this as opposed to nasty chemical ridden sprays for everyone" .