Doppelgangers Catnip - Bring Your Cat to the Dark Side - 2 ounces of Farm Fresh Catnip in clear re-sealable pounch *2 ounce resealable pouch *Fine Cut Catnip *Farm Fresh from Canada * The principal natural constituent of catnip is nepetalactone, which is what makes most cats respond to catnip. However, not all cats respond to nepetalactone.