These work very well for our little 11-pound yorkie.  We got them to use when we moved to a new house and to help with her separation anxiety.  They really seem to help calm her down a bit without making her drowsy.  I definitely recommend giving them to your dog at least 30 minutes before an event, such as taking them to the vet, in order to give them plenty of time to work.  Also, the calming effect doesn't seem to last more than a couple of hours, but overall they worked for us very well!