The evidence for homeopathy, or more specifically the evidence that it is effective beyond a placebo, is far from compelling. While the burden of proof still lies with homeopaths and alternative medicine practitioners to prove its effectiveness, conventional medicine has put it through its paces with a series of trials and meta-studies. The evidence can be split into two categories; the first is that looking at the efficacy of homeopathy, the second is looking into the physical claims such as water memory and quantum woo.
 Medical evidence
There have been several major investigations into homeopathy. The Lancet, one of the world's premier medical journals, has published a few fairly high quality meta-studies, and the Cochrane Collaboration, practically the place for meta-studies, has also released a few studies. In general, these studies come out negative in favor of homeopathy, although keeping with a scientific view of having an open mind some do conclude "insufficient evidence"; while there isn't enough data to conclusively prove that homeopathy is hokum, there isn't any reliable data pointing towards it having a real and tangible effect. Serious, high quality research has only been recently available.
 The Lancet, 1997
A large study from 1997 looked at 186 trials, using 119 of them based on inclusion criteria and determined a small, apparently positive, effect of homeopathy, although nothing conclusive. The paper states; "the results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homoeopathy are completely due to placebo. However, we found insufficient evidence from these studies that homoeopathy is clearly efficacious for any single clinical condition. Further research on homoeopathy is warranted provided it is rigorous and systematic." (emphasis added). So while the 1997 survey didn't generate strong evidence to say that homeopathy was bullshit, it didn't offer any proof that it had a genuine clinical effect. The study attracted some criticism that the authors' "prejudice in favour of homoeopathy is obvious". However, Klaus Linde defended the study and welcomed the criticism, recognising the flaws in corrections of publication bias (a complex topic), the fact that inconsistent methods of action for the placebo effect could generate further confusing data, and requesting others to look at the data carefully.
In 1999 Linde and his team Published a followup acknowledging that:
The evidence of bias [in the primary studies] weakens the findings of our original meta-analysis. Since we completed our literature search in 1995, a considerable number of new homeopathy trials have been published. The fact that a number of the new high-quality trials ... have negative results, and a recent update of our review for the most "original" subtype of homeopathy (classical or individualized homeopathy), seem to confirm the finding that more rigorous trials have less-promising results. It seems, therefore, likely that our meta-analysis at least overestimated the effects of homeopathic treatments.
The process of science means that it would be misleading and wrong to quote the first finding without noting the second. But who would do such a thing?
 Cochrane Collaboration, 1998
The meta-studies performed by the Cochrane Collaboration are regularly updated. Its study on homeopathic treatment of chronic asthma was first published in 1998 and reassessed/updated in 2007. The report looked at various trials of differing quality and "pooled" results, meaning that different remedies were tested, each with a potentially different contribution, and included nearly 600 people. Despite this high risk of bias and false positive results, it found insufficient evidence for a conclusive answer, and certainly no reliably positive effect. The authors concluded that few studies seemed capable of assessing the "package effect", that whereby the non-clinical aspects of the treatment, such as extended consultations and additional woo-ing of patients can contribute greatly to the placebo effect. While such calls for additional or better research are scientifically accurate and honest (although slightly unhelpful) where the data truly is limited, they have drawn criticism from some doctors and researchers, citing that patients are owed more than non-committal statements. This is especially valid given the "extraordinary claims require extraordinary evidence" position taken by skeptics; as homeopathy is an extraordinary claim and "inconclusive" is far from extraordinary evidence.
 The Lancet, 2005
The 2005 meta analysis published in The Lancet examined 110 controlled studies of homeopathy and 110 studies of matched conventional medicine studies. The Lancet study showed that there was no effect beyond that of a placebo for homeopathy. This massive undertaking examined a large amount of evidence and was systematically - i.e., fairly - constructed and carried out. The authors concluded that "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." (emphasis added) The study was criticised by Klaus Linde (author of the 1997 study above) for its high risk of generating a false-positive when restricting itself to larger studies only and pooling the data, as the efficacy of homeopathy may vary across different treatments. He did, however, agree with the conclusion. Shang et. al. responded openly to the criticisms by Linde and others and rectified some of the concerns such as the criticism of using 8 larger trials out of 110 to draw conclusions.
 Eur. J. Cancer, 2006
In 2006 European Journal of Cancer showed no effect of homeopathy in a meta-analysis of 6 studies.
 J. Alt. Med., 2006
Even sympathetic researchers have problems. Homeopathic practitioners published a study performed in Honduras in the Journal of Alternative Medicine that showed homeopathy to have no effect treating diarrhoea.
 Positive trials
Some published positive evidence for homeopathy does exist and these papers are often cited repeatedly by practitioners. However, these studies tend to have many methodological flaws and such flaws make the data less reliable. Ineffective blinding (where people may have been aware that they were receiving administering a placebo rather than treatment) has been known to overestimate the efficacy of a treatment under study by 17%. In addition, ineffective randomisation (where the researchers could choose, consciously or subconsciously, who received the treatment and who received the placebo) can overestimate efficacy by around 30-40%. Taking into account the methods used when analysing data is particularly important if the papers don't mention their methods; i.e., they may have something to hide. When taking into account data from flawed experiments and accounting for the flaws, homeopathy still comes out as no more effective than a placebo.
Homeopathy apologists will also point to the small number of slightly positive results within the higher quality study outcomes, failing to note that it is in the nature of any trial process that the usual confidence interval of p=0.05 means that one in twenty positive results will be false positives. Such apologists prefer to focus on the "problem" of false negatives, which according to them explains the fact that virtually all methodologically sound tests deliver negative results. This is because of Reasons. Definitely.
 Physical evidence
- See the main article on water memory
 Water clusters
One of the key goals for modern homepaths is to prove the existence of special properties of water or any solvent that allow them to be clinically active despite having no active ingredient in them - i.e., are just pure solvent. This includes the succussion process that supposedly imparts the memory onto the solvent. These claims aren't entirely beyond medical or scientific testing. As with the medical evidence, this is currently lacking. Some research shows water exists as small, fluxional clusters and dimers in both solution and the gas phase due to its strong propensity for hydrogen bonding. However, these do not explain water memory as they are neither long-lived enough or are affected by a succussion procedure.
At least two studies on homepathic solutions by NMR spectroscopy found no difference. This was true of relaxation times, a property of water protons that can be easily measured in a magnetic field. Another study looked at the actual spectrum of water produced by NMR. The conclusion was again negative as despite many new NMR signals appearing in the study, most were identified as artifacts, and the rest as known or unidentified impurities and none were found more frequently or specifically in the homeopathic remedies than in the controls.
 We forgot this bit
Even if there were unambiguous evidence of the existence of water memory, this would still not offer any significant support for homeopathy; it would have to be shown that:
- The effect is as stated, i.e. the remedy does what the provings claim (many substances are listed with thousands of symptoms).
- The effect is persistent.
- The effect increases with increasing dilution.
- The effect produces a distinct difference between different source substances.
- The effect can be transferred to a sugar pill once the water has evaporated.
- The effect can be passed to the human body through the enzymes which dissolve the sugar pill.
- The effect can then increase within the body to produce measurable curative effect.
- The effect is specific and will be delivered to the correct part of the body (homeopathy discusses left and right side remedies even where there is no anatomical distinction).
This list is by no means exhaustive.
One of the key features of any clinically active medication is the ability for it to have an overdose effect. Although this may be very high, or even too high for it to be practically consumable, it is still there - for instance, vitamin C overdoses, paracetamol overdoses that damage the liver, as well as over-hydration by consuming too much water, which is considered to be one of the main causes of death in ecstasy related fatalities. In the case of homeopathic remedies, no such observation is made. This is often cited as a good thing by homeopaths as their remedies cannot possibly cause damage; however, this is very much evidence against the remedies having an active clinical effect beyond a placebo (just to reiterate, the placebo workings of homeopathy aren't denied).
The 10:23 Overdose Event was designed to highlight this fact, as 400 homeopathy skeptics simultaneously "overdosed" on store-bought homeopathic remedies. Similarly, James Randi often consumes as many as 100 homeopathic sleeping tablets (a fatal overdose for even the mildest of genuinely active medications) at the beginning of many of his performances and speeches. In a more serious case from late 2009, Alexa Ray Joel, daughter of musician Billy Joel, attempted suicide by consuming Traumeel, a homeopathic remedy for joint pains that is also claimed to act as a sleeping aid. Needless to say, all of these people are alive and well, and it may be the case that Alexa Ray Joel specifically took homeopathic pills so they wouldn't really kill her.
 What if...
Author Jay W Shelton in Homeopathy: How it really works identifies many contentious issues in homeopathy which are resolved, removed or unnecessary if it is allowed that the remedies themselves are inert, and that the effect is solely down to the placebo effect brought on by the consultation process aligned with the natural history of the disease, regression to the mean and other external factors. These include:
- The lack of empirical evidence for the law of similars is no longer an issue.
- The absence of evidence to support the law of infinitesimals is similarly no longer an issue.
- The numeorus inconsistent theories of homeopathy including classical homeopathy, clinical homoepathy, isopathy, tautopathy and so on are entirtely resolved as the common element (the sympathetic office visit) can be allowed to account for the common effect.
- The fact that homeopaths believe everything is a potential remedy - including imponderables (electricity, light), inert substances (water) and substances which at pharmaceutical doses have measurable physiological effect - is no longer a problem.
- Imponderable remedies that have no atoms to start with would no longer be doubly inexplicable.
- Remedies diluted past the Avogadro limit no longer need a separate explanation.
- It would no longer be necessary to explain why the "memory" of a substance would be more effective then the substance itself.
- The claim that remedies are equally effective for the same ailments in (physiologically distinct) reptiles, birds, and mammals is no longer a problem.
- An explanation would no longer be needed for how, in tautopathy, the remedy fights the side effects of conventional drugs but not their intended primary action.
- No explanation would be needed for how a remedy knows to represent only the intended initial medicinal ingredient and not all the contaminants that enter at every stage of the process.
- An explanation would no longer be needed for exactly why the same pill can induce and cure the same symptoms (in provings and with patients, respectively).
- The details of succussion would no longer matter - pounding the bottle on a leather book, or shaking it, or stirring it would all have the same noneffect; the debate over Hahnemannian versus Korsakovian methods for making remedies would be unnecessary. No explanation would be needed for why triturated remedies are just as effective (or ineffective) as succussed remedies even though the processes are very different. Grafting and "plussing", stated to be effective without succussion, would also no longer need to be explained. Remedies made by placing water or unmedicated pellets on paper with a remedy's name written on it would be as active as any others.
- The fact that provings with the highest methodological quality tend to produce the fewest symptoms attributable to the remedies would make sense since the other causes of symptoms are accounted for and excluded.
- No post-hoc rationalisation is required for the fact that in some provings, the effects are said to be felt by people not even taking the remedy. Provings in which no one takes the remedy at all (dream, trituration, and meditative provings) likewise become uncontentious: the remedy does nothing, therefore the proving is as valid with as without it.
- The fact that provings show the same remedy to cause opposite symptoms (for example, constipation and diarrhea) would no longer need explanation.
- No recourse is needed to the "healing crisis", "Hering's laws" or any other ad hoc explanation for the observed fact that administration of the remedy can cause the symptoms to improve, worsen, or stay the same, and all are asserted as evidence of homeopathy "working".
- There is no need for any appeal to quantum woo to account for the action of remedies in which nothing remains of the original substance.
- There is no need to account for the fact that homeopaths cannot tell one remedy from another when blinded.
- There is no tension between homeopathy and the observed fact that high methodological quality trials show the remedy itself to be irrelevant.
All these and many other conflicts between homeopathy and the reality-based community would be effectively removed if it is allowed that the remedies themselves are inert, consistent with the predictions and measurements of science. This explanation of homeopathy alone is fully consistent with the principle of parsimony and is consistent with all the observed evidence. It is considered unlikely that homeopathy will accept this argument, however.
 See also
- List of scientifically controlled double blind studies which have conclusively demonstrated the efficacy of homeopathy
- ↑ Klaus Linde, Nicola Clausius, Gilbert Ramirez, Dieter Melchart, Prof Florian Eitel, Larry V Hedges, Dr Wayne B Jonas MD The Lancet, Volume 350, Issue 9081, Pages 834 - 843, 20 September 1997
- ↑ Klaus Linde, Wayne Jonas; Meta-analysis of homoeopathy trials
- ↑ Linde, K; Scholz, M; Ramirez, G; Clausius, N; Melchart, D; Jonas, WB (1999), "Impact of Study Quality on Outcome in Placebo-Controlled Trials of Homeopathy", Journal of Clinical Epidemiology 52 (7): 631–6, doi:10.1016/S0895-4356(99)00048-7
- ↑ Cochrane.org -Homeopathy for chronic asthma
- ↑ Hopfenspirger, M. "A more skeptical review of homeopathy" Otolaryngology - Head and Neck Surgery
- ↑ Aijing Shang MDa, Karin Huwiler-Müntener MDa, Linda Nartey MDa, Peter Jüni MDa, b, Stephan Döriga, c, Jonathan AC Sterne PhDb, Daniel Pewsner MDa, d and ProfMatthias Egger MD, The Lancet, Volume 366, Issue 9487, 27 August 2005-2 September 2005, Pages 726-732
- ↑ Klaus Linde, Wayne Jonas - Are the clinical effects of homoeopathy placebo effects?
- ↑ Aijing Shang et. al. - Are the clinical effects of homoeopathy placebo effects? — Authors' reply
- ↑ Milazzo S, Russell N, Ernst E Efficacy of homeopathic therapy in cancer treatment. Eur J Cancer. 2006 Feb;42(3):282-9.
- ↑ Jacobs J, Guthrie, B, Montes G, Jacobs L, Colman N, Wilson A, DiGiacomo R. Homeopathic Combination Remedy in the Treatment of Acute Childhood Diarrhea in Honduras. The Journal of Alternative and Complementary Medicine. 2006 Oct;12(8):723-732.
- ↑ British Homeopathic Association - Here they state that 44% of trials were positive while 7% were negative. Although true, this is misleading as it is the quality of research that is important and the research with positive conclusions tend to be very flawed. The major meta-analyses into homeopathy take this into account.
- ↑ Kenneth F. Schulz; Iain Chalmers; Richard J. Hayes; Douglas G. Altman - Empirical Evidence of Bias: Dimensions of Methodological Quality Associated With Estimates of Treatment Effects in Controlled Trials. JAMA, Feb 1995; 273: p.408 - 412.
- ↑ David Moher, Ba' Pham, Alison Jones, Deborah J Cook, Alejandro R Jadad, Michael Moher and others - Does quality of reports of randomised trials affect estimates of intervention efficacy reported in meta-analyses?. The Lancet, Aug 1998; 352, 9128: p.609-613
- ↑ Science Based Medicine - Fun with homeopaths and meta-analyses of homeopathy trials
- ↑ Aabel S, Fossheim S, Rise F. - Nuclear magnetic resonance (NMR) studies of homeopathic solutions
- ↑ Anick DJ, - High sensitivity 1H-NMR spectroscopy of homeopathic remedies made in water
- ↑ 1023.org
- ↑ Alexa Ray Joel, daughter of Billy Joel, addresses overdose