Kava Bones

I saw a few articles on Kava Herbs and then ran across a company selling dog Kava Bones as treats. Evidently, the kava herbs help in relaxation and anxiety. The site stated that they would help your dog with separation/anxiety attacks when you were away. They also stated that they were totally safe and harmless as far as side effects or health problems.
Can anyone confirm this to be safe? If so, are kava bones actually effective?
Thanks, I love this forum!!