Henry's mom,
I think you're in Ontario as well, and I use sentinel... I think you can get it at any vet's around here... could be wrong though, I can't back that up!
But it does work for those things (worms, etc). It also prevents fleas from breeding, but doesn't prevent them from landing and biting, like advantage does.
I just went with sentinel because it comes in pill form (advantage is a smelly liquid you apply to their skin) and it's easier.
