It depends on who you are going to treat? I am assuming you are speaking about how to treat your cat, but I honestly don't know anything about that. I do know that if you or someone in your family has it, you can buy Clotrimazole cream for it. I work in the Pharmacy business, so I get asked this question quite a bit. The cream is a antifungal medicine and is usually found in the athletes foot section of most drug stores. Make sure you wash your hands completely...you can spread it to others!
Just thought I'd share that with you and the best of luck with your ringworm problem.