Thrush is a fungal infection, so an anti-fungal product should be used as a preventative. Anti-Bac, formulated by Cecil Swan, is both an anti-bacterial and anti-fungal hoof dressing that can be applied to the hoof every day. It works well and is cheaper than Thrush Buster. If your horse develops thrush, Thrush Buster will get rid of it. Basically, Anti-Bac prevents thrush in the first place, and Thrush Buster treats it.