Frontline is just for external parasites. It needs to be applied every 1-3 months. I guess it depends on how much you use or something. I only use about 3 drops on a large breed bird.I have and I should again, I use cayenne too some. I might just do that and see what happens first. I have some frontline I plan to put on them. I have never done that. Does that kill internal worms too?