Such levels are generally along the lines, from top to bottom, of meta-
analyses of randomised controlled trials (RCTs), systematic reviews, limited
evidence from RCTs, cohort studies, case-controlled studies, case series,
case reports, expert opinion and anecdote drawn from one or a few isolated
observations.^13 What is missing from hierarchical lists is a place for ‘anec-
dotal knowledge’ at a level higher than ‘anecdote’ and ‘expert opinion’.
Anecdotal knowledge (or evidence) is that which has been built up over an
extended period of time among generations of practitioners and others who
develop a specialised knowledge (e.g. herbalists, ‘wise women’), through
their own experiences, and from comparing these with others of colleagues,
in either consultations or published reports. Anecdotal knowledge not only
is a feature of much aboriginal/traditional medical practice, but also has
long been a key element of conventional medical practice.^14 Although
constantly diminishing as a result of the development of modern pharma-
cology and clinical trials, anecdotal knowledge for treating individual
patients remains an everyday part of conventional medicine; even so it is
commonly overlooked by those – perhaps more by younger practitioners
still close to their medical education – who fail to see an existing paradox,
namely conventional medicine’s claim to be a positivist science despite
the uncertainties of clinical practice in interpretation, flexibility and
practicality.^15
Judgement of the robustness of evidence embedded in anecdotal knowl-
edge is problematic, even though evaluation is more at the level of evidence
accepted in civil prosecutions, namely ‘more likely than not’, rather than the
criminal standard of ‘beyond a reasonable doubt’.
Examples of applying the three-step approach to herbal remedies in
aboriginal usage
Selection of examples of herbs out of the vast armamentarium of aborig-
inal/traditional remedies (with much regional variation) is not easy. The two
chosen (alder and black cohosh) have been selected to illustrate different
challenges in response to questions about aboriginal usage. Alder, unlike
black cohosh, has not become a major dietary supplement and few scientific
data are available to assist in evaluation. In contrast, the top-selling black
cohosh has been subjected to many laboratory and clinical studies, albeit
with inconsistent findings. At least both herbs reflect a widespread belief
that a core of empirical knowledge, long held by herbalists (some called
yerberos), lies behind the use of herbs – a view that underpins much research
on constituents of aboriginal and other traditional medicinal plants. On the
other hand, whether or not some form of ceremony or ritual accompanied
the administration and contributed to therapeutic benefits is not always
clear (see below).
Aboriginal/traditional medicine in North America | 49