We live in a society that embraces things for being “alternative.” And that’s fantastic. If that wasn’t the case, American Idol would be the only show on TV, and Radiohead’s new album (or the seven before it) would hardly be the talk of the town. In other words, the world would be a far less interesting place.But the alternative route becomes a problem when an idea gains merit simply for being unorthodox — when going against the status quo is sufficient to garner credibility. The field of homeopathy has been riding this wave for more than 200 years.In the popular understanding, homeopathy is readily lumped in with all things alternative and “natural.” Yet, rather than being a hazy branch of complementary medicine, it is actually a field with a unique history and a wealth of literature to boot. Its skeptics are fierce, and its proponents still fiercer. Welcome to Homeopathy 101.When the 18th century drew to a close, the German physician Samuel Hahnemann came up with a rather outlandish notion: that the best way to treat a disease was to use a substance that induces its symptoms in a healthy individual. Considering that his peers were busy bloodletting and prescribing leech therapy, this idea may not have seemed too far from the norm.The theory was inspired by Hahnemann’s reaction to cinchona bark, a common treatment for malaria at the time. Since ingesting cinchona made him feel “languid and drowsy,” symptoms which he felt were similar to those of malaria, Hahnemann concluded that this property must be essential to its medicinal effects. Thus, the field of homeopathy was born.
But there was a problem here. People were probably not too fond of taking medicines which had been specifically chosen to induce the symptoms they were already suffering from. To get around this inconvenient hurdle, Hahnemann added a further innovation to his recipe. He decided that the more you dilute a substance, the more you can “potentize” its healing abilities.Any old dilution wouldn’t do the trick. In order to be effective, this procedure had to be carried out by administering ten hard strikes against an elastic object (a process referred to as “succussion”). Only then would you be able to activate the “spirit-like essence” of the substance being diluted.What’s more, it’s remarkable how much diluting it takes to release the genie in the homeopathic bottle. We’re not talking about a splash of water in our whisky here. Homeopaths measure dilution on a centesimal (or C) scale, which involves diluting a substance by one part in 100 at every step. Given that your typical homeopathic treatment comes at a dilution of 30C, that equates to a dilution factor of 10 to the power of 60.To put this in perspective, skeptics have noted that a dilution of 12C is the equivalent of adding a pinch of salt to the Atlantic Ocean. Quite some splash of water.It’s convenient, then, that central to the current homeopathic philosophy is the idea that the elaborate process of succussion leaves an imprint of the diluted substance on water, or a “water memory.” The fact that this notion is widely refuted by physicists, chemists, and common sense alike is apparently of little concern to the homeopath.Today, the concepts of “like curing like,” potentization, and extreme dilution persist largely unchanged within the homeopathy industry. In fact, they form the basis of a huge number of “remedies” in the homeopathic arsenal.Whether or not you find these ideas credible is a matter of individual judgment. Personally, I like to have at least 12 molecules of active ingredient in any medicine I take. But that’s me. The seeming impossibility of the method should not be the sole reason for dismissing homeopathy. After all, there are more things in heaven and earth than are dreamt of in our philosophy.What really matters is the clinical evidence for homeopathy. Specifically, how does it measure up under the inspection of a controlled clinical trial?When it comes to this pivotal question, there is a huge amount of evidence out there — enough to give ammunition to both sides of the debate. Even for the hardened observer, the prospect of trying to unravel the key message from this tangled web of data can be rather daunting.To help resolve this issue, it’s time to introduce another key concept of clinical science: the meta-analysis. Don’t be put off by the scary terminology. A meta-analysis essentially involves combining all the data from multiple, small trials into a single coherent analysis, then seeing which way the weight of evidence leans. It’s a pretty logical concept, and it might not be too unfamiliar. Rotten Tomatoes has been doing exactly the same thing for film reviews for years.Crucially, a meta-analysis can reveal a significant clinical effect for a particular intervention when each individual trial had failed to recognize it. Alternatively, this method can dispel the apparent virtues of a treatment when some of the smaller trials might suggest otherwise. This makes it the perfect tool for examining the clinical evidence on homeopathy.So what do the meta-analyses (and there have been several) have to say on the matter?Perhaps the most comprehensive of these studies, examining 110 independent trials on homeopathy, was published by Professor Matthias Egger in The Lancet in 2005. In each trial, the therapeutic effect of a homeopathic treatment was measured (basically, did the intervention do anything?). But perhaps more importantly, the quality of each study was scrutinized. For instance, how big was it? Was it randomized? And was it blinded? All important stuff, which can drastically influence the outcome of a clinical investigation.Here’s what it boiled down to (cue drum roll): while small, low quality trials often reveal a therapeutic effect for homeopathy, the better the study, the smaller this effect tends to be. And if you look exclusively at the largest, most scrupulous trials, homeopathy performs no better than placebo.When it comes to issues of public health, we deserve the undiluted truth. If a remedy does not contain a single molecule of active ingredient, and cannot weather the scrutiny of a controlled clinical trial, it probably shouldn’t form the basis of a multi-billion dollar global industry.Conventional medicine is far from flawless. It is built, however, on a system of constant re-evaluation, in which obsolete and ineffective practices are cast aside. Somehow, homeopathy has escaped the scrapheap.Read Headlines on trial: The power of evidence