Feuding Kitties

Question
Hello Dr. Fry,
   We have two cats,both of which we love very much- but they hate eachother. This causes a problem because,obviously, it stresses them out; but it has also caused us to have to put one of the kitties, Shadow, outside for most of the time. Their main battle ground is the litterbox, and as a result of the other kitty using every litterbox we put out in the house, Shadow pees by them to mark her territory and pees all over the rest of "her territory" as well. Shadow also ambushes the other kitty when she is in the box. We have taken Shadow to the vet to rule out any medical problems behind this, and we beleive that it is a behavioral issue, because Shadow seems to have no trouble using the litterbox for the rest of her business. She also won't urinate on the floor if there is nothing like a towel or carpet to urinate on.
My question is: Is there any way we can help the cats to get along? And might we be able to train Shadow not to pee anywhere but the box? We don't like having to cut Shadow off from the family, although she and the other cat seem happier when she is outside. Thank you for your time and happy holidays- Claire Parker

Answer
I would recommend getting Feliway/Comfort Zone diffusers and place several of them in the house to help reduce stress and anxiety.  Feliway is also very useful for urine marking.  

It sounds that Shadow may benefit from some anti-anxiety medication such as Amitriptyline to help her with her underlying anxiety.   

Try flower essences such as Rescue Remedy in the water dish to see if that helps.

Cat Attract litter may help draw her back to the box. www.preciouscat.com

And rule of thumb is one MORE litter box than the number of cats.