I've never had the need. But a dear friend of mine who has a a 5 pound chihuahua/poodle mix uses it on her dog, and says it made a big difference. The dog is still anxious during thunderstorms and other loud things like fireworks, but nowhere near as bad. She'll actually sit on her owner's lap instead of trying to hide behind the toilet or trying to get into the space that's just a bit too small for her, between the refrigerator and the wall....poor thing