Mark, I had the same problem you had when trying to find Sustical. I tried all of the pet stores. Then someone told me that it can be found in Drug Stores and grocery stores. It's a non-lactose based dietary supplement for humans. It comes in a lot of flavors. I use vanilla, but I hear that some ferrets like strawberry. I guess any flavor except chocolate will do. Dick B. [Posted in FML issue 0989]