Great aid in treating horses and ponies for thrush caused by organisms susceptible to copper naphthenate. Thrush is a disease of horses" hoofs characterized by a thick, black, foul-smelling discharge. 7 oz. Aerosol, Horseshoer"s Secret Thrush Treatment Aid goes on only where you need it. Contains copper naphthenate. Water resistant formula. Official Product Of RHE American Farrier"s Association, FDA Approved.