120], scientists have difficulty in regarding this form of alternative medicine as any more than a placebo effect.e A controversial paper in Nature  containing data from several laboratories, claiming to prove the efficacy of extreme dilution (the 'memory of water' )a has not been generally accepted after the results were reported as not reproducible under closely controlled and observed (by Nature's self-acknowledged biased observers), but strained, overly-demanding and unsympathetic, conditions with negative results from only one laboratory being cherry-picked from amongst otherwise positive results . The original results  were, however, confirmed in a blinded study by the statistician Alfred Spira [346e] and also in a rather bizarre Nature paper purporting to prove the opposite [346b],b were subsequently comprehensively confirmed by a blinded multi-center trial [346a], and new results confirm similar phenomena . In spite of this apparent confirmation by several laboratories, there are still doubts over whether the experiments are truly reproducible and whether the noted effects may be due to the origin of the biological samples or human operator effects . Further support for an effect has been found using NMR .
Meta-analysis of 89 placebo-controlled trials failed to prove either that homeopathy was efficacious for any single clinical condition or that its positive clinical effects could entirely be due to a placebo effect [121a], thus leaving the scientific door open both ways. A further analysis of this data, however, indicated that some of these studies may have failed to avoid bias and that studies using better methodology yielded the less positive effects [121b]. A recent analytical review has reinforced the, more negative, view concerning the clinical effectiveness of homeopathic remedies . Further, a recent quality assessment of published experiments on homeopathic preparations has concluded that many were performed with inadequate controls . Although a scientific trial of homeopathy conducted for the BBC and similar work reported on ABC News' 20/20 program both failed to show any homeopathic effect, the experiments they reported have been subject to serious criticism including that of careless scientific methodology. In August 2005 , the medical journal 'The Lancet' controversially argued for halting any further research into homeopathy concluding it has no effect other than as a placebo. This judgment was based on its simultaneous publication of a comparative study of 110 matched placebo-controlled trials of homeopathy and conventional medicine . The conclusion was reached, however, in spite of the study apparently showing little evidence of differences between the two groups (homeopathy and conventional) when all the data was considered. There were differences when a tiny percentage of unmatched larger trials were cherry-picked for further analysis (that is, 102/110 of the homeopathy studies and 104/110 of the conventional studies were discarded).c The remaining 6% of the studies, however, still showed positive (if not conclusive, possibly as the number of trials left in this final grouping was so small and unmatched) evidence in favor of a homeopathic effect over placebo. Although this study has come in for considerable and rightful criticism, and there is a strong case for its retraction, as above and [1381, 1382, , it is often put forward in support of the view that homeopathy works no better than as a placebo; a fact that it clearly does not deliver.
495]. Changes in the thermoluminescence of ice produced from ultra-diluted water have been noted [500a] but can be explained by remaining trace amounts of material (due to poor mixing, impurities, absorption, nanobubbles (that is, nanocavities) [500d] or other causes) being concentrated between ice crystals [500b]; an explanation supported by later work [500c]. Changes in the NMR relaxation times [1620a, 1620c], thermochemistry  and UV absorption [1620b] of water in some homeopathic preparations remain unexplained and require confirmation.
A key feature of any difference between water before and after its use in preparing homeopathic dilutions is likely to be the vigorous shaking (succussion) that must be carried out between successive dilutions, and which may produce significantly increased concentrations of silicate, sodium and bicarbonate ions [335, 1207] by dissolution of the glass tubes and increases in nanobubbles and redox molecules [1066, 1751] from the atmosphere, respectively. Recently, a paper from Nobel prize-winning Luc Montagnier has declared that quite dilute solutions (of DNA) show entirely different properties from the less diluted solutions, that the authors propose depend on interactions with the ambient electromagnetic field .f How water may show a memory is explored further in the 'memory of water' page.
Footnotesa Note that 'memory of water' effects (if proven) not only require the solution to retain information on dilution but clearly require this information to be amplified to negate the effect of the dilution.
b This paper was bizarre as the data it produced that showed a positive effect (therefore actually supporting the 'memory of water' conclusions) were dismissed by the Authors out of hand as 'a source of error for which we cannot account' so leaving the remaining data (that is, only the data which agreed with their headline). It should be noted that the statistical report on which this paper was based states that ' One interpretation is that there are, after all, differences between the treatments...' [346c] but this statement does not survive into the final version published by Nature. The Authors have apparently refused to release their raw data [346d] for unbiased statistical analysis. Nature also recently published a paper on 'ultrafast memory loss' in water that, perhaps ingenuously, appears to misinterpret this 'memory of water' concept, as it only concerns the 'memory' of single water molecules, not clusters of water molecules .
c The 'cherry-picking' is clear as (although a rationale for some sort of selection is presented post hoc) the study does not appear to have used a pre-determined rationale (or pre-determined parameters) in discarding trials, completes no sensitivity analysis and ends up apparently 'dredging' the data in an unbalanced manner, to falsify conclusions . Further analysis of the data, provided post publication, shows that the conclusions would have been different for almost all alternative cut-off points ; that is, they would not support the conclusions that homeopathy is no more than a placebo effect or that homeopathy trials are less good than conventional trials.
d This 'dilution' is usually so extreme that no molecules of the starting material are expected to be found in the final 'solution'. In spite of this, the efficacy (and cost) of the homeopathic remedies are often thought to be greater, the greater the dilution.
e It should also be noted that placebo effects constitute real clinical effects [121c], should be judged positively and probably account for a significant proportion of the success of prevailing established medicine . Also, there must be a range of 'placebo effects' of different potencies and having different effects in different situations. As such, they surely overlap with true clinical effects. As an example, it seems clear that antidepressant medications used for many years are not efficacious and any perceived difference from placebo is due to the reduced responsiveness to placebo in the severely depressed .
f The extraordinary results given in this paper have yet to be independently confirmed.
Author: Martin Chaplin. Emeritus Professor of Applied Science. BSc PhD CChem FRSC. London South Bank University. Curriculum & Selection of Recent Publications.