Several months ago, a number of doctors banded together to denounce homeopathy as unproven and a waste of the National Health Service's limited resources. Periodically, the medical profession has offered similar 'proof'. But what does the scientific literature actually say?
On May 23 of this year, 13 semi-eminent British scientists and doctors signed a statement-with all the stylistic authority of a Papal Edict-condemning homeopathy as "unproven or disproved". No doubt about it, they said, homeopathy is useless, and a waste of money, too. They urged the NHS to stop using it-a negative message widely accepted by the media, at least initially.
Was there anything to the attack? The primary claim of the 13 signatories was that homeopathy is "an implausible treatment for which over a dozen systematic reviews have failed to produce convincing evidence of effectiveness". Sounds totally damning, but is it true? Let's take it point by point.
"Implausible". Certainly, homeopathy is at variance with both conventional scientific theory and the dominant medical model of disease and how to treat it. But implausibility is not a criticism. History is littered with examples of once implausible ideas that are now accepted-aeroplanes, meteorites and continental drift, for example. In medicine itself, helicobacter pylori as a cause of ulcers, folic acid as a preventative of neural-tube defects, and acupuncture used for anaesthesia are just three of the ideas that were considered ludicrous and are now considered fact.
"Over a dozen systematic reviews". That's an underestimate. In fact, an in-depth survey in 2001 located 22 "systematic reviews of clinical trials" of homeopathy in the medical literature (BMC Complementary and Alternative Medicine 2001, 1: 4). That survey was carried out five years ago, and there have been two major clinical reviews since then. So, two dozen would be a more accurate figure.
"Failed to produce convincing evidence". This is the nub of the issue. The word "convincing" is key. Note that the 13 signatories are not saying there's no evidence, it's just that that these particular individuals aren't persuaded by it. Well, that's hardly surprising, given that some of them are (or at least were) members of either Quackwatch or COPUS (Committee for the Public Understanding of Science)-organizations dedicated to rooting out the "irrational" in science and medicine.
However, putting their personal prejudices aside, is there any objective merit to their attack? Let's look at the real evidence.
The 2005 Lancet study
Doubtless, uppermost in the minds of the 13 would have been a very recent survey of homeopathy, conducted by Swiss researchers less than a year ago (Lancet, 2005; 366: 726-32). This attracted a lot of publicity at the time, partly because Dr Richard Horton, the Lancet editor who published the report, penned an accompanying editorial, "The End of Homeopathy", which condemned homeopathy outright: "Now doctors need to be bold and honest with their patients about homeopathy's lack of benefit." Although it wasn't made clear in the media reports, the Lancet study wasn't an actual test of homeopathy. The Swiss researchers did no clinical investigations of their own; it was entirely a paper exercise. What they claimed to have done was an objective assessment of 110 clinical trials of homeopathy-the ones they considered passed a minimum quality standard (roughly 60 per cent of the published trials to date).