Muscle relaxer, used it for a big muscled horse to help with muscle soreness, it worked good for what I wanted, did not cause a sedative affect on my horse but I have read that it can do this to some horses. Kind of a pain to give as it is a fairly large amount of pills and you have to give them twice a day I think, there is an injection also but again it is a large amount to inject, I also think they give this to horses when they are tying up but not totally sure about that.