you guys talking about Valium gave me another idea. Have you ever heard of a DAP Diffuser? Its used for dogs with anxiety problems. DAP stands for Dog Appeasing Pheromones. The pheromone used is the one that a lactating mother releases which gives the puppies a sense of well-being i believe.
check it out:
http://www.healthypets.com/dapdogappher.html
they also come in a collar form.