Just had to throw in my two cents worth. I've seen giant fatty tumors in a dog reduce like in half(the owners stopped CS usage). Small one in dogs and cats just go away completly. Concerning the kidney issue, if you are feeding your dog a high protein dog food, this might be the cause. Several years ago the same thing with my dog. At the time, the food I was feeding him had over 30% protein. He's been on a lower protein content dog food since then and he hasn't any problem. He's a big dog and will turn twelve in a few days.