Stronghold prevent heartworms but it doesn't treat it. So if you have suspicion that your cat has heartworm, it would be good idea to get your cat tested. If she/he has heartworm you would need a different medicine to treat it. This product wouldn't have any extra side effect if they have heartworms, but it won't treat it either.
By Deborahchelettewilson den 10. december 2014