Advance Access Publication 26 January 2006eCAM 2006;3(1)145–147
Homeopathy and The Lancet
Director of Research, Royal London Homoeopathic Hospital, Great Ormond Street, London WC1N 3HR, UK
The Lancet of August 27, 2005 featured a cluster of articles
highly critical of homeopathy which attracted considerable
media attention. The media reports echoed The Lancet’s press
release: ‘homeopathy is no better than placebo’. The center-
piece was a meta-analysis of clinical trials of homeopathy
compared with clinical trials of allopathy (conventional
medicine) (1). The first author is Aijing Shang, but the leader
of the research group is Prof. Matthias Egger of the Depart-
ment of Social and Preventive Medicine, University of Berne,
The meta-analysis formed part of the Complementary
Medicine Evaluation Programme (Programm Evaluation
Komplementa ¨rmedizin, PEK) financed by the Swiss Federal
government. The international review board of PEK has
publicly protested at political interference in the scientific
process: ‘There is a consensus among the review board
members that the final PEK process deviated from what
would have been expected by conventional standards. Espe-
cially disconcerting was the fact that the products of the
PEK process—health technology assessment (HTA) reports,
single description of studies, manuscripts for publication and
the condensed final report—were sent to the board members
but no discussion, comment, or review was solicited by the
responsible agencies’ (2).
The meta-analysis was accompanied by a short, anonymous
editorial entitled ‘The end of homoeopathy’ calling for
‘doctors to be bold and honest with their patients about homeo-
pathy’s lack of benefit, and with themselves about the failings
of modern medicine’ (3); and a more thoughtful commentary
from the Dutch epidemiologist Jan Vandenbroucke, reflecting
on the ‘growth of truth’, including the relationship between
bias, background knowledge and the concordance of clinical
results with laboratory science findings (4). Vandenbroucke
concludes that the proof of the pudding is in the eating: the
ultimate proof of the validity of a scientific or medical idea
is extent to which it changes reality.
The same issue of The Lancet featured a leak of the World
Health Organisation’s (WHO) draft report on homeopathy.
The WHO document was apparently leaked to The Lancet by
Dutch and Belgian doctors hostile to homeopathy; their com-
ments and the (hostile) comments of Prof. Edzard Ernst of
the University of Exeter were published. Dr Xiaorui Zhang,
Traditional Medicine Coordinator of WHO, who is responsible
for the report, was also interviewed, but declined to comment
on a leaked, confidential draft. This leak came only 2 days
after The Times of London published, as its front page lead, a
remarkably similar story: a leak of the Smallwood Enquiry
on The Role of Complementary and Alternative Medicine in
the NHS commissioned by The Prince of Wales’ Foundation
for Integrated Health. It is ironic that the editor of The Lancet,
Dr Richard Horton, wrote to The Times accusing Prof. Ernst of
having ‘broken every code of scientific behaviour’ for leaking
the draft report of the Smallwood Enquiry (and incidentally
describing complementary medicine as ‘a largely pernicious
influence... preying on the fears and uncertainties of the
sick’), while simultaneously doing the same to the WHO
report in his own journal!
Dr Horton also wrote an open letter to the UK Secretary
of State for Health, Patricia Hewitt and the Chairman
of the National Institute for Clinical Excellence (NICE)
Prof. Sir Michael Rawlings, calling for the use of homeopathy
in the NHS to be reviewed in light of this publication.
The meta-analysis at the centre of the controversy is based
on 110 placebo-controlled clinical trials of homeopathy and
110 clinical trials of allopathy (conventional medicine), which
are said to be matched. These were reduced to 21 trials
of homeopathy and 9 of conventional medicine of ‘higher
quality’ and further reduced to 8 and 6 trials, respectively,
For reprints and all correspondence: Peter Fisher, Director of Research, Royal
London Homoeopathic Hospital, Great Ormond Street, London WC1N 3HR,
UK. Tel: +44 (0) 20 7391 8890; Fax: +44 (0) 20 7391 8829; E-mail:
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which were ‘larger, higher quality’. The final analysis which
concluded that ‘the clinical effects of homoeopathy are
placebo effects’ was based on just the eight ‘larger, higher
quality’ clinical trials of homeopathy. The Lancet’s press
release did not mention this, instead giving the impression
that the conclusions were based on all 110 trials.
The criteria for the matching of the homeopathic and con-
ventional trials were not clearly stated, and it is evident from
the numbers above that the clinical trials of homeopathy and
conventional medicine were not, as claimed, well matched—
the homeopathic trials were generally of better quality. And
this is a crucial parameter [as Shang et al. (1) acknowledge];
it is well established that high quality trials are less likely to
be positive than those of lower quality. Because of the
individualization involved, it is difficult to do large-scale trials
of homeopathy (again this is evident from the figures
above), so the final sample is unlikely to be representative of
trials of homeopathy. An example is a study that may have
been included in the final eight, which looked at the use of a
homeopathic medicine for prophylaxis of influenza, an indica-
tion for which it is not recommended, and obscured the identity
of the homeopathic medication (5). However, a Cochrane
Review has concluded that it is probably effective for treat-
ment (as opposed to prevention) of flu-like illnesses (6). A
number of similar instances could be cited, but since we do
not know which studies are under discussion, there is little
Transparency, Sensitivity and
One of the most serious criticisms is the complete lack of
transparency: we have no idea which eight trials were included
in the final, damning, analysis. The literature references are
not given, nor any information on the diagnoses, numbers
of patients, etc., nor can these be deduced from the article.
Prof. Egger has refused several requests to disclose the iden-
tity of the eight trials. This is not even a matter of scientific
method, but of natural justice: the accused has the right to
know the evidence against him.
Meta-analysis should incorporate sensitivity analysis. In this
case the obvious sensitivity analysis is to look at the 21 trials of
‘higher quality’, particularly since it appears that the criterion
‘larger’ appears to have been added retrospectively to ‘higher
quality’. But the result of this analysis was not published.
This meta-analysis assessed quality purely in terms of
internal validity. Internal validity is the extent to which a trial
measures what it purports to measure; external validity the
extent to which what it measures is meaningful in the real
world. This is an important concept, best explained by an
example. A clinical trial of homeopathy in childhood asthma
by White et al. (7), published in Thorax in 2003, was reported
as showing that homeopathy is ineffective. This trial was
of high internal validity because, among other things, it used
a predefined primary outcome measure: quality of life as
measured by the childhood asthma questionnaire.
The results showed no difference in the quality of life scores,
although the secondary outcome measures (such as severity
and time lost from school), consistently favored homeopathy
over placebo. However, because quality of life was the primary
outcome, the authors reached a negative conclusion. But, as
was pointed out several times in the ensuing correspondence,
this conclusion was meaningless because of a ‘ceiling effect’:
the children had normal quality of life when they entered the
study, and this could not have been expected to improve fur-
ther! (8–11) This study was of high internal validity but very
low external validity, but would have been classified ‘high
quality’ in The Lancet meta-analysis.
Upper Respiratory Tract Infections
Shang et al. (1) state that ‘eight trials of homoeopathic reme-
dies in acute infections of the upper respiratory tract ... indi-
cated a substantial beneficial effect ... sensitivity analyses
might suggest that there is robust evidence that the treatment
under investigation works. However, the biases that are preva-
lent in these publications, as shown by our study, might pro-
mote the conclusion that the results cannot be trusted’. They
state that eight studies is too few to question their conclusion
about the whole set of publications. Their conclusion about
the whole set, however, was also based on eight studies. Is
eight enough for a conclusion or not? Or does it depend on
what that conclusion is?
But perhaps the most telling single criticism of this
meta-analysis is that it fails, on multiple counts, to meet
the generally accepted standards for meta-analysis—the
QUOROM statement (Quality of Reports of Meta-Analyses
of Randomised Controlled Trials), published in The Lancet
itself in 1999 (12). The main failings are those outlined
above, although there are others.
The implausibility of homeopathy is an important Bayesian
prior for Shang et al. (1), but they fail to quote emerging evi-
dence for in vitro activity of ultramolecular dilutions (13,14)
which has important implications for the implausibility of the
claims made for homeopathy.
This meta-analysis is subject to fundamental criticisms.
Regrettably, the media have already reported The Lancet’s
version of the story. Homeopathy’s popularity is growing
worldwide despite many such attacks. To paraphrase Mark
Twain, reports of the death of homeopathy are much exagger-
ated: the facts simply are incompatible with The Lancet’s
claim that the end of homeopathy is nigh. Regrettably, this
attack will only widen the divisions. The way forward is
open, transparent science, not opaque, biased analysis and
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Summary Consensus Statement of the PEK Review Board regarding the
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