It's called Kava Kava, I've never used it before, but I know some of my clients use it. It seems to work well, it's like a person drinking a cup of chammamile (sp?) to calm down or relax. It works in the same way. A lot of people have said that kava kava also can help with behavior problems in dogs such as excessive barking, anxiety and stress. It's safe for both cats and dogs, but if you are nervous about giving to him you should talk to your vet.