I first bought this for my sister because her dog was dealing with some very serious separation anxiety. He cried and howled every time she left for work, sometimes urinating on the floor and other things. It worked well, not completely, but it helped. I then tried it for my dog who has gets really upset when we have company come over. I bought two diffusers. I put one in the living room where the company would be and I put a second one in my bedroom where my dog would hide. The improvement was dramatic. My dog now comes out and hangs out with the company, he doesn't whine or shake anymore, and he doesn't hide at all.