studies of dietary supplements, and some of those
studies are sponsored by the manufacturers who
have an economic investment in positive outcomes.
Too often, studies of dietary supplements are small,
poorly designed, poorly controlled, or incompletely
reported, making it is difficult to draw hard conclu-
sions about the effectiveness and safety of the product.
The most common use of echinacea in the United
States and Europe is to prevent or shorten and reduce
the severity of symptoms of the common cold, includ-
ing sneezing, runny, nose, cough, and fever. Natural
Standard, an independent organization that evaluates
studies, scientific evidence, and expert opinion on com-
plementary and alternative treatments and makes
impartial judgments concerning their safety and effec-tiveness has found that the evidence of effectiveness of
echinacea in treating cold symptoms is mixed. Some
studies have shown that individuals who take echina-
cea during cold season are less likely to catch a cold,
but more have found that echinacea has no effect on
whether an individual catches a cold. On the other
hand, more than half of a substantial number of well-
designed European studies found that people who take
echinacea at the first sign of a cold feel better sooner
than those who take a placebo or who take nothing.
These results have been contradicted by several large,
well-designed American studies, including one in 2005
of children ages 2–11 that found on average echinacea
did not reduce the length of time the children showed
cold symptoms. Two studies sponsored by NCCAM
also found echinacea did not shorten the symptoms of
colds or influenza or prevent colds.
For years, echinacea has been taken to improve
general health and to treat a variety of infections
because it is thought to boost the immune system.
Laboratory analyses of the ingredients in echinacea
and some animal studies have suggested that echina-
cea does stimulate immune system cells. However, this
result has not been confirmed in humans. Research
continues on this use of echinacea.
Claims have also been made that individuals with
AIDS, cancer, and genital herpes can benefit from
taking echinacea. Although there is some theoretical
basis for these claims, there is no clear evidence that
echinacea has an effect on these conditions in humans.
Despite mixed evidence about the effectiveness of
echinacea, the herb generally appears to be safe when
taken by adults in moderate amounts. There is no
standardization of the amount of active ingredient in
products containing echinacea. Guidelines of normal
doses for a 150 lb (70 kg) adult taken three times a day
are:
1–2 g dried leaves or root brewed into tea
2–3 mL tincture
200 mg powdered extract
Lower doses of echinacea for children, based on
the weight of the child, are generally thought to be
safe, although in the cold study mentioned above,
children showed an increased risk of developing a
rash. One study of pregnant women using echinacea
found that moderate use of the herb during the first
three months of pregnancy did not increase the like-
lihood of the baby being born with major birth defects.
The safety of echinacea use inbreastfeedingwomen
has not been adequately studied.KEY TERMS
Alternative medicine—A system of healing that
rejects conventional, pharmaceutical-based medi-
cine and replaces it with the use of dietary supple-
ments and therapies such as herbs, vitamins,
minerals, massage, and cleansing diets. Alternative
medicine includes well-established treatment sys-
tems such as homeopathy, traditional Chinese medi-
cine, and Ayurvedic medicine, as well as more-
recent, fad-driven treatments.
Complementary medicine—Includes many of the
same treatments used in alternative medicine, but
uses them to supplement conventional drug and
therapy treatments, rather than to replace conven-
tional medicine.
Conventional medicine—Mainstream or Western
pharmaceutical-based medicine practiced by med-
ical doctors, doctors of osteopathy, and other
licensed health care professionals.
Dietary supplement—A product, such as a vitamin,
mineral, herb, amino acid, or enzyme, that is
intended to be consumed in addition to an individ-
ual’s diet with the expectation that it will improve
health.
Perennial herb—A plant that lives for several years
with new growth appearing each year.
Placebo—A pill or liquid given during the study of a
drug or dietary supplement that contains no medi-
cation or active ingredient. Usually study partici-
pants do not know if they are receiving a pill
containing the drug or an identical-appearing
placebo.Echinacea