Shockingly, a systematic review in the August 27 Lancet concludes that homeopathy is probably worthless:
Biases are present in placebo-controlled trials of both homoeopathy and conventional medicine. When account was taken for these biases in the analysis, there was weak evidence for a specific effect of homoeopathic remedies, but strong evidence for specific effects of conventional interventions. This finding is compatible with the notion that the clinical effects of homoeopathy are placebo effects.(no free full text but citation is Shang et al. Lancet 2005 366:726)
As an accompanying editorial notes, what is surprising is not the finding, but that we are still having this debate. Of course with a President (and, worse, a Senate majority leader who is both a presidential hopeful and a transplant surgeon) advocating teaching of intelligent design, how much can we expect.
As Vandenbroucke notes in his accompanying editorial (page 691 of same issue):
In 1846, John Forbes compared homoeopathy and allopathy, mostly informally, but also with a few shrewd experiments. He found the results of homoeopathy for certain ailments as good as those of his own treatments. Because he considered the theory of increased potency by greater dilutions “an outrage to human reason”, and therefore any effect of homoeopathy impossible, he proposed that his findings should lead to introspection about the effectiveness of the allopathic medicine of his time.Unfortunately more than 15o year laters, homeopathy is a billion dollar business. I've always said the great weakness of economics was its assumption of rationality, and the dollars spent on "alternative" health care are about the best refutation of that assumption I can muster.