There's a lot of snake oil outside of traditional medicine, but there's a lot of it *within* traditional medicine as well.
One of the really obvious low-hanging fruit that I've seen is the Burzynski Clinic.
To summarize, Stanislaw Burzynski (a doctor in Texas) claims to have invented a new cancer treatment that's better than Chemo. Someone made a movie "Cancer is serious business" which shows lots and lots of case file evidence that this is true.
We have a claim, and we have evidence. Is this bunkum or a scientific breakthrough?
It's usually easy to figure this out: interview the patients, see if they were treated, if they got better (or not), and if they are happy with the treatment. Examine the evidence and see if it's consistent with the claims.
In most cases of "bunkum", you'll find that the patients feel they were cheated, the treatment had no effect, they were also on traditional treatments, and so on and so on. It's pretty easy to separate the wheat from the chaff by examining the evidence.
In the case of Stanislaw Burzynski, no one does this. Read up on the reports and find that no one addresses the evidence directly: it's all ad-hominem attacks ("he's not a real doctor, he's not a cancer researcher"), indirect rationalizations ("it can't work because it doesn't fit my model", he doesn't have an explanation for *why* it works, it must be bunkum because it's too good), administrative accusations, and so on and so on.
One particularly salient point, brought up by many, is that the treatment is "untested". His treatment doesn't work because there are no studies to confirm this.
No one addresses the evidence.
I think what medical science, and science at large, have to realize is that people are starting to wise up to these "absence of evidence" statements. Just having a doctor say "there are no studies showing it's effective" won't cut it any more - it's seen as a verbal hand-waving to support schools of thought. It's "absence of evidence is evidence of absence".
This is what happened with Homeopathy. People had a rationalization for *why* it works and there was some historical evidence. Add in some first-hand accounts, and suddenly you've got a miracle cure that science can't explain (but really works!).
Not every crazy theory needs a full-fledged study, but I suspect a lot of good could be done by taking the top "fad" populist beliefs and making simple, definitive studies. I'd feel a lot more comfortable if a doctor could say "we studied it and there's no effect" instead of "there's no evidence that this has any effect".
The prior shows a logical certainty, the latter is rationalization.