We bought a Feliway diffuser as we were having problems with Whisper scratching the wallpaper and spraying around the house by our outdoor cats, who are all neutered males.  This has only happened since we introduced Tiffany, a spayed female.  We are pleased and delighted to report that both problems seem to have been solved!  No more damage has been done to the wallpaper and no more evidence of spraying has been noticed.  Although the cats were tolerating each other, they were obviously stressed, but what we have now is a more harmonious feline household.

Biscuit & Cookie