TJ > google the placebo effect, then come back to me.
I'd also recommend reading badscience.net (and buying the book). Oh, and search on YouTube for Dara O'Brien's 'homeopathy' sketch, the man speaks sense.
The only 'alternative' medicine which isn't nonsense is the stuff that also appears in conventional medicine. Ie, commercial drugs are sometimes based in nature, and the equivalent natural remedy will also have the same base active ingredient, just packaged differently.
To paraphrase the aforementioned O'Brien, just because science doesn't understand everything doesn't mean we get to make stuff up.