All of the remedies listed have some evidence of
effectiveness, although this
varies greatly from plant to plant. The ability of
ginkgo (Ginkgo biloba) to
improve memory and prevent dementia is strongly
supported by research
evidence. On the other hand, the use of chickweed (Stellaria
media) to soothe itchy
skin and eczema has never been researched, and
rests upon traditional
knowledge and direct experience. The safety of
herbal remedies, and
their effectiveness as medicines, is not necessarily
easy to establish. By and
large, knowledge about how herbs work comes from:
• Use as food or a food supplement.
• Traditional knowledge of use as a medicine.
•
The experience of herbal practitioners.
- Scientific Research
Nutrition
Remedies such as garlic (Allium sativum), lemon (Citrus
limon), oats (Avena sativa),
and soy (Glycine max) form a regular part of many
people’s diets, and
are therefore used as both food and medicine.
Long-term food use confirms
that the remedy is safe to take as a medicine,
although it tells one little
about its effectiveness in this respect. Some
herbal remedies contain
significant levels of nutrients and are taken as
nutritional supplements, for
example, kelp (Fucus vesiculosis). Such use comes
from scientific investigation
of the plant’s constituents.
Knowledge
The strength of traditional medicinal systems such
as Ayurvedic (India/Sri Lanka),
Chinese, and Western herbal medicine lies in the
fact that knowledge and experience of remedies has been built up over thousands
of years, constituting what
has been described as the longest-ever clinical
trial. Put to the test of time, it
is argued, few herbs that are harmful or
ineffective will remain in popular
use—only those found to be safe and effective will
retain their place. Longstanding use of a herbal remedy can therefore be seen
as a strong indicator of safety and usefulness, although it is not a guarantee.
Experience
Trained herbal practitioners develop a practical,
subtle understanding of how
best to apply herbal medicines and are watchful for
signs of side effects. They
are able to select those remedies most likely to
help a patient. The collective
experience of herbal practitioners—for example,
caution in giving devil’s claw
(Harpagophytum procumbens) to patients with acid
indigestion—can give
important pointers to the safety and effectiveness
of remedies.
Research
Scientific investigation into a medicinal plant
spans a multitude of different
types of research which add, like pieces in a
jigsaw puzzle, to the overall picture.
Researchers can investigate:
• The chemistry of the plant—its constituents and
their actions.
• The whole plant—parts used, actions, uses, safety
issues, and so forth.
• Processing—how to extract and process the remedy.
• Clinical trials—the therapeutic use of a plant
extract, including dosage
levels, safety, and evidence of effectiveness.
On one level, the chemistry of the plant, or
phytochemistry, underpins all
aspects of herbal research. If you know the key
chemical constituents of a
plant, you can make a reasonable guess about its
level of safety and value as a
medicine: caffeine is a key constituent in coffee (Coffea
arabica), cola, guarana
(Paulinia cupana), mate (Ilex paraguariensis), and
tea (Camellia sinensis).
Its stimulant activity forms part of the action of
each plant.
Yet, each plant also has its own unique activity
and character. The natural complex of constituents found within a herbal remedy—the
“whole”— is more than its key active constituents— “the sum of its parts.” This
interplay or synergy between different constituents is often a factor in the
safety and effectiveness of an herbal medicine (see also Types of herbal
remedy, pp.30–33). Good clinical trials compare the safety and efficacy of an
herbal medicine against another medicine or a placebo (a dummy product). Data collected
from these trials provides the strongest evidence of just how safe or effective
an herbal remedy is.
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