http://www.smartgroups.com/message/readmessage.cfm? gid=1423922&messageid=14364&startid=14366 Revolution in the US is labeled as effective against the American dog tick only. I suspect that that is because they have not yet gotten the studies to show efficacy against other tick species, but it could be a true distinction. Dr. Ruth ******************************************** Puppies kiss better than most people. [Posted in FML issue 4907]