“I switched to this product after one of my dogs got worms. I was shocked that he had worms because he had been on preventive meds for years but once I looked at the package I discovered it didn't prevent this specific worm ( I don't recall which worm) I literally spent about 8hours straight researching heartworm+ meds and this one covered most of the bases. I looked at statistics, like - side effects effectiveness, Etc. and I researched parasites prone to my region (GA). I researched every heartworm medicine available in the US and Canada and Interceptor plus fit the bill for me. no issues after 6months of use on 1 large dog and 1 small dog (both mutts w/allergies). I plan to stick with this until there's a reason not to.”