The biggest difference between Heartguard and Iverhart is the Iverhart is flavored with pork rather than beef for those dogs who have problems with the beef flavoring ingredient in the Heartguard. The other difference is the Iverhart has an extra ingredient ( Praziquantel) that takes care of tape worms where the Heatguard does not. It is a matter of personal preference on this situation. Joan
This link explores the differences between the two medications......