I just wanted to point out that just because something is seen as outside of the conventional scientific wisdom, that doesn't mean that it is not amenable to scientific study. Psychic phenomena are being studied scientifically at a number of universities, including Edinburgh. One famous psychology experiment, which I believe has been replicated a number of times, shows that those who believe in paranormal phenomena actually perform better in tests of psychic abilities, performing slightly above chance levels. This suggests that there is something in what they believe, and that psychic experiments should take into account the beliefs of the subjects.
Peg said "For example, one of the main arguments against the efficacy of herbal remedies is that they have not and in some cases cannot be "proven" to be effective (and so remain unregulated by the FDA), but ONLY because the scientific testing grounds, set up for synthetic drugs and those manufactured in a laboratory, cannot encompass the many variables inherent in botanical substances. This includes differing concentrations of various chemical constituents which vary from crop to crop, given variations in weather, climate, soil, growing conditions, harvesting, drying and preservation tachniques, etc. But just because science cannot effectively measure the effectiveness of these substances in ways that suit their methods, doesn't mean they don't work...Ask anyone who has used chamomile to sleep, guarana to be more alert, willow bark for a headache, raspberry leaves for menstrual cramps, fennel for an upset stomach... "
If the variables you mention would have so much of an effect that the substance tested did not show a clear effect in experiments, that is a sign that ordinary people taking these herbs might have a similarly inconsistent experience. If it is the case that a particular way of growing/drying/preserving etc is important in the effect the herb has, then that is the form of the herb that should be tested - and then surely a significant advantage (over placebo) would be shown for these substances if they are in fact beneficial. Its not that science cannot effectively measure the effectiveness, but that trials to date have not taken into account all the variables they need to control. That is a fault with scientists, not with the scientific method.