Great question! I use Sentinel once a month with Mercola Natural Defense Flea and Tick Spray (made with natural oil) twice a week, and this has worked pretty well, but we’ll see what happens in the summer. Then again, I live in California, so we don’t really have much of winter. 😀
I’m not a fan of spot-on topical flea preventatives, and I am not sure if it would be okay to combine them with an oral one. The ingredients are different, so it would probably be okay, but I would recommend using a natural option, or at least checking with your vet/the company first.
One note on Diatomaceous Earth, if you use it make sure it is food-grade, and try to keep you and your pet from inhaling it.
