Only a few herbs have been
studied in randomized, double-blind, clinical
trials, the type of study that provides the
strongest evidence for the effectiveness of a
medical treatment. Without the kind of evidence
that comes from a clinical trial it is very
difficult, if not impossible, to judge the
safety and efficacy of herbal medicines. In the
absence of evidence from a clinical trial, the
potential effectiveness of an herbal medicine
can only be judged based on traditional use or
research that can only assess one narrow aspect
of an herbal medicine. For example, there are
cellular and animal studies that can give an
estimate of the biological activity of herbal
medicines and their potential for various
treatments, but these studies poorly reflect
their safety and efficacy in the human
body. Nonetheless, a single clinical trial can
give misleading results. Consistent results from
several well designed and conducted clinical
trials are needed to be sure a medicine is safe
and effective.
In herbal medicine, the understanding of the
effectiveness of treatments is most often based
on experience from traditional use. But reports
of this type are not very dependable and may not
reflect the medicines current use and possibly
its abuse. A recent example is ephedra or ma
huang. This herbal medicine was marketed to
promote weight loss and to increase athletic
performance. Ephedra has been described as one
of the oldest herbal medicines and has been used
without adverse effects in traditional Chinese
medicine for more than 5000 years for the
treatment of respiratory problems and asthma.
However, in April 2004 the U.S. Food and Drug
Administration (FDA) banned its sale. After
receiving reports of at least 100 deaths and
almost 17,000 adverse effects linked to the use
of this herbal medicine, the FDA ordered a
review of its safety. This review evaluated the
safety of ephedra from the clinical trials
examining this medicine (50 trials). It found
that ephedra use was linked to a two to three
fold increase in the risk of high blood
pressure, heart palpitations and psychiatric
disorders. These risk levels lead the FDA to
determine that “ephedra posed an unreasonable
risk to those who used it.”
Conventional medicine has come to have more
of an appreciation of the potential of herbal
medicine and a number of the more commonly used
herbal medicines have been evaluated in clinical
trials.
A
lot of herbal products are of a low standard. That's why I recommend a product from
a reputable company and clinically approved. Just because
herbal medicines are “natural” products does not mean they are
safer than conventional medicines. The ingredients in herbal
medicines, that can lead to health problems or adverse effects,
are generally found in lower amounts in plants, making it more
difficult to get a large dose. But many herbal medicines are
concentrated to increase effectiveness and this process may also
eliminate this potential ‘margin of safety.’ Detection of
adverse effects is also more difficult for herbal medicines as
they are currently marketed in the U.S. 