In this post on boingboing, Xeni Jardin - who’s currently being treated for cancer - suggests that purveyors of fake cancer cures are murderers. I agree with her for the most part. I think the ones who’re not deliberate charlatans are fear-driven zealots.
I’m suspicious of most “alternative” medicines, because if a treatment works, it quickly becomes mainstream. If it’s been around for a while, and it’s “alternative,” that means it doesn’t work.