I agree with other reviewer about this product -- it's very cat-specific in terms of which ones like it or not. It works. A cat either likes it from the start or doesn't, and that preference persist.  The ones that like it, LOVE it -- and I can't accidentally leave it on the counter since it will end up with puncture marks from them trying to bite into it.  The ones that aren't interested weren't interested from the start.  FWIW, adding some mineral oil to a cat's wet food is welcome by all of mine, so to the extent one of the cats don't take the petromalt, the mineral oil helps to keep the hairball situation under control.  Mineral oil is odorless and tasteless, so I don't get the fascination with it, but cats will be cats. . . .