Z-Itch Pour on Solution for Horses is a ready to use pour-on solution that’s ideal for combating sweet itch. Z-Itch Pour on Solution for Horses may be used as an aid in the control of sweet itch especially for the control of the biting insect Culicoides spp. Treatment should be started at the beginning of the sweet itch season and repeated as necessary. Once weekly should be sufficient for most horses. Contains permethrin 40mg/ml.