I don't trust homeopathy, partly due to the fact that the homeopathic substance is watered down to the point where the probability that any one "dose" will actually contain the substance itself is very low.

I also don't trust the idea that placebo works due to some mind over matter deal. When the measure is subjective, as in depression, it's possible that thinking that you're on a medication will cause you to answer a depression quiz differently, without actual general improvements in mood. Maybe it's comparable to an observation with porsches one psychologist made--having a porsche makes people happier when they're thinking about how happy the porsche makes them, rather than the rest of the time.

Placebo's purpose is to provide blinding for the intervention. But where is the blinding for placebo itself? One study looked at giving people placebo, but telling them that it was placebo. The placebo still worked--but the subjects were told that placebos have a powerful mind-body effect, going in.