At first my cat was not sure what these crystals were and was very reluctant to go near his box... He thought they were food, or a new "toy" of some sort, it seemed. After he finally decided they wouldn't hurt him, he was perfectly fine with them. They seem to really absorb the "cat" smell conventional litter leaves and you use far less than normal litter also. Plus if kitty kicks a couple crystals on the ground and you step on one in the middle of the night or whatnot, you won't really even feel it. I highly recommend!!