Herbalism is defined as the study and use of plant material as food and
medicine for healing and health promotion. Both art and science, herbalism has
been practiced for centuries. Although botany describes an herb as a low-growing
nonwoody plant, herbalists make use of the entire plant kingdom (Meserole 1996).
Long practiced outside of conventional medicine, herbalism is rapidly becoming
mainstream, as analysis and research of herbal constituents and activities
explore their value in the treatment and prevention of
Archeological findings suggest that plants had been used for medicinal
purposes long before recorded history. Indigenous cultures (e.g., African and
Native American) incorporated herbs into their healing rituals, while
traditional medical systems (e.g., Ayurveda and Traditional Chinese Medicine)
developed systematic uses for herbal therapies. Ancient Chinese writings from
more than 5,000 years ago, and Egyptian papyrus writings, circa 2,000 B.C.E.,
describe medicinal plant uses (Chavez and Chavez 2000). Ethnobotanists have
discovered that widely separated groups of people have a tendency to use the
same or similar plants for the same purposes (D'Epiro 1999).
Although most traditional herbal uses were derived through observation,
sensory perception, sacred teachings, and intuition (Meserole 1996), Western
herbal medicine has been influenced by the development of the scientific method
and by subsequent advances in analytical technology. In the early 19th century,
when methods of chemical analysis first became available, scientists began
manipulating plant materials by extracting their active principal ingredients,
and by chemically modifying isolated ingredients to reduce side effects and
enhance therapeutic properties. Later, chemists began synthesizing organic
compounds, and practitioners began the transition from raw herbs to synthetic
pharmaceuticals (Chavez and Chavez 2000). In 1870, the United States
Pharmacopeia listed 636 herbal entries; by 1990, only 58 were listed. Some herbs
were dropped from the list because they were considered unsafe or ineffective;
however, the decline in Western herbalism through the 1930s is due largely to
regulatory and economic factors that favored pharmaceuticals and the
practitioners trained to use them (e.g., medical doctors) (Meserole 1996; Chavez
and Chavez 2000).
Recently, the World Health Organization estimated that 80% of people
worldwide rely on herbal medicines for some aspect of their primary health care.
In the last two decades in the United States, increasing public dissatisfaction
with the cost of prescription medications, combined with an interest in
returning to natural or organic remedies, led to an increase in sales of herbal
medicines of 59% in 1997 (Chavez and Chavez 2000). In Germany, approximately 600
to 700 plant-based medicines are available and are prescribed by an estimated
70% of German physicians (D'Epiro 1999).
Herbalists often use whole plant extracts containing multiple constituents on
the theory that these ingredients collectively reduce the side effects of any
individual constituent (a mechanism known as "buffering") and provide
synergistic actions as well. In addition, herbs are generally used in
combinations, rather than singly. Using several herbs together is likewise
thought to augment synergistic activities, enhance efficacy, and reduce toxicity
(Vickers and Zollman 1999).
Diagnosis and treatment are based on the herbalist's understanding of the
whole person—body, mind, and spirit (Meserole 1996).
Diseases are perceived within the context of the entire system, and the
diagnosis may include reference to secondary symptoms (e.g., arthritis due to
inflammation secondary to poor elimination) (Vickers and Zollman
|Mechanism of Action|
Western science ascribes herbal mechanisms of action to plant
constituents—carbohydrates, tannins, lipids, volatile
oils, resins, steroids, alkaloids, peptide hormones, enzymes, etc. Therapeutic
actions of plants may be influenced by: species, variety, and the individual
plant itself; habitat, including such variables as weather and climate,
companion plants, pests, and soil; composition and constituents; collection,
storage, processing, dispensing, and dosing; presence of adulterants,
contaminants, or plant disease; the patient's age, health status, disease, and
receptivity to healing; the symbolic or cultural significance of the plant; and
the placebo effect (Meserole 1996). For most herbal medicines, the exact
compound that produces the pharmacological action is unknown and any therapeutic
effects are most likely the result of synergistic action among herbal
constituents (Chavez and Chavez 2000).
An office visit to an herbalist typically lasts one hour and includes an
extended history and physical examination. Particular attention is paid to the
patient's general sense of well-being, sleep quality and patterns, diet and
appetite, digestion and elimination, exercise habits, and relaxation
preferences. Practitioners typically recommend one or more herbs, dietary
changes, and lifestyle modifications. Because herbal medicines are slower acting
than pharmaceuticals, patients return for follow-up in two to four weeks.
Treatment goals are to correct imbalances, resolve patterns of dysfunction, and
treat the underlying cause. Symptomatic treatment may also be initiated, as
necessary (Vickers and Zollman 1999).
Herbalists treat many conditions such as asthma, eczema, premenstrual
syndrome, rheumatoid arthritis, migraine, menopausal symptoms, chronic fatigue,
and irritable bowel syndrome, among others. Although herbal preparations are
best taken under the guidance of a trained professional, many patients
self-medicate with herbals (Vickers and Zollman 1999). Some of the most common
herbs and their uses are discussed below.
Ginkgo (Ginkgo biloba), particularly a standardized extract known as
EGb 761, appears to offer some benefit in the treatment of Alzheimer's and
multi-infarct dementia. Ginkgo crosses the blood-brain barrier, acts as a
cerebral antioxidant, and improves cerebral oxygenation (D'Epiro 1999). A
52-week, randomized, double-blind study of 309 Alzheimer's patients given either
placebo or EGb 761 (40 mg tid, before meals) revealed consistent improvements in
cognitive performance and social function in the EGb 761 group, while the
placebo group worsened over the same period. Two hundred and two subjects
completed the study (50% of the EGb group; 38% of the placebo group). Other than
occasional reports of mild to moderate gastrointestinal symptoms, adverse events
in the EGb group were no different from those for the placebo group (Le Bars et
Kava kava (Piper methysticum) is being investigated for its anxiolytic
activities. Kava extract (WS 1490), standardized to 70% kavalactones, was
compared to placebo in a 25-week double-blind trial involving 101 male and
female outpatients diagnosed with one of four anxiety disorders as defined by
DSM-III-R diagnostic criteria. The patients in the WS 1490 group started the
trial with a mean score of 30.7, and the placebo group with a mean score of
31.4, as assessed by the Hamilton Anxiety Scale. Pronounced improvements were
seen in the WS 1490 group in weeks 12 (mean score 13.4) and 24 (mean score 9.7).
The placebo group also improved in weeks 12 and 24, but to a lesser extent (mean
scores 18.0 and 15.2, respectively). Adverse events in the WS 1490 group
occurred in two subjects who experienced stomach upset (Volz and Kieser 1490). A
six-week, double-blind, comparison study evaluated the efficacy of kava (210 mg)
and either oxazepam (15 mg) or bromezepam (9 mg) in 164 patients suffering from
nonpsychotic anxiety, tension, and agitation. At the end of the six weeks, there
were no statistical differences among the three groups as evaluated by the
Hamilton Anxiety Scale, with each compound effectively reducing anxiety by
approximately 10 points (Woelk et al. 1993). This suggests that kava may be at
least as good as the benzodiazepines used in this trial for treatment of
St. John's wort (Hypericum perforatum) is well known for its
antidepressant effects. In 1994, German physicians prescribed St. John's wort
more often than any other antidepressant. St. John's wort contains 10
pharmacologically active constituents but is generally standardized to 0.3%
hypericin, which may not be the only therapeutic compound involved (D'Epiro
1999). A meta-analysis of 27 randomized studies involving a total of 2,291
patients provides evidence that St. John's wort is significantly superior to
placebo in the treatment of mild to moderate depression (Linde and Mulrow 2000).
Seventeen trials were placebo-controlled, and ten were comparison studies using
pharmaceutical sedatives or antidepressants but not selective serotonin reuptake
inhibitors (SSRIs). Study length varied from four to six weeks and patient
inclusion criteria were based on conventional classification systems (e.g.,
DSM-III and DSM-IV). Most outcomes were measured by the Hamilton Depression
Scale or the Clinical Global Impressions assessment tools. More recently, in a
double-blind, randomized pilot study, St. John's wort was found to be as
effective as sertraline, an SSRI, in the treatment of mild to moderate
depression (Brenner et al. 2000). Both St. John's wort and sertraline were well
tolerated in the latter study.
Valerian (Valeriana officinalis) has had a long tradition as a
sleep-inducing agent. Its actions are similar to those of benzodiazepines;
however, hangover effects have not been reported (D'Epiro 1999). Valerian is
thought to induce an increase in gamma-aminobutyric acid (GABA) levels in brain
synapses, thereby inducing an anxiolytic effect (Ernst 1999). A randomized,
double-blind, placebo-controlled, crossover study evaluated the short-term
(single dose) and long-term (14 days with multiple doses) effects of valerian
extract on objective and subjective sleep parameters. Sixteen patients with
established primary psychophysiologic insomnia were included in the study. Sleep
efficiency was measured by eight polysomnographic recordings: two recordings
(baseline and study night) at each time point that valerian and placebo were
tested. Other objective sleep structure parameters were measured by sleep-stage
analysis and arousal index. Subjective measures included quality of sleep,
feeling in the morning, daytime performance, and perceived length of sleep
latency and sleep duration. Single-dose valerian resulted in no effects on sleep
structure or subjective sleep assessment. Multiple-dose treatment, however,
showed a significant increase in sleep efficiency for both placebo and valerian
in comparison to baseline polysomnography and parameters describing slow-wave
sleep (SWS). Reductions in SWS latency and subjective sleep latency were
observed in the valerian group, with an increase in SWS time in bed and a higher
correlation coefficient between subjective and objective sleep latencies (Donath
et al. 2000).
Echinacea preparations (from Echinacea purpurea and other
Echinacea spp.) are reported to have immune-stimulating functions,
including increasing the number of leukocytes and spleen cells, and enhancing
the activity of granulocytes. In addition, echinacea increases the release of
tumor necrosis factor and inhibits hyaluronidase activity, thereby optimizing
the ability of the immune system to withstand microbial infections (D'Epiro
1999). In a double-blind, placebo-controlled study of 160 volunteers with
flu-like symptoms, echinacea extract demonstrated the ability to reduce both the
incidence and severity of cold symptoms (Braunig et al. 1993; Schoeneberger
|Risks, Side Effects, Adverse
Although herbs, when properly prescribed, are generally thought to offer
fewer risks than conventional medications, misidentification, mislabeling,
self-prescribing, allergic reactions, undeclared additives, and adulterants
increase the likelihood of adverse effects (Chavez and Chavez 2000). Other risks
involve interactions between herbs and conventional medications (see
Contraindications section) and herbal prescribing by unqualified practitioners
(Vickers and Zollman 1999). Some known risks of herbal use include dermatitis
from garlic (Allium sativum), photosensitivity from St. John's wort,
hepatotoxicity from echinacea, excessive sedation from valerian, agitation from
feverfew (Tanacetum parthenium), gastrointestinal irritation from
chamomile (Matricaria recutita), and hormonal changes from ginseng
(Panax spp.) (Miller 1998). In a study involving 3,250 patients, the most
frequently reported side effects of St. John's wort included gastrointestinal
irritation, allergy, fatigue, and restlessness, with a total of 2.4% (79
patients) reporting such symptoms (Woelk et al. 1994). Valerian has demonstrated
paradoxical stimulant effects in approximately 5 to 10% of users (D'Epiro 1999).
Ginkgo, along with feverfew, garlic, ginger (Zingiber officinale), and
ginseng, may alter bleeding time (Miller 1998).
Most contraindications involve drug-herb interactions. Some of the more
important interactions are listed below.
St. John's wort induces the cytochrome P450 system, particularly the
subenzyme CYP3A4, resulting in a doubling of CYP3A4 activity. This effect has
significant ramifications for clearance and efficacy of medications also
metabolized by this system (McIntyre 2000). In particular, NIH researchers
investigating a possible interaction between St. John's wort and the protease
inhibitor indinavir found that plasma concentrations of indinavir dropped
significantly from levels obtained prior to the introduction of this herb. The
Food and Drug Administration (FDA) has issued a public health advisory
concerning this interaction based on the study results. (See monograph on St.
John's wort for further details.) Also reported in the same monograph is a case
report of two patients who experienced episodes of heart transplant rejection
when taking cyclosporine and St. John's wort. Cyclosporine levels were
significantly lower during use of St. John's wort; when the herbal treatment was
discontinued, cyclosporine levels returned to therapeutic range.
Herbs that increase bleeding time (such as ginkgo, feverfew, garlic, ginger,
and ginseng) should be administered with caution when using anticoagulant
therapies. Ginseng use may cause additive effects with estrogens or
corticosteroids. Valerian should not be used with sedatives such as barbituates
because of a risk of excessive sedation. Oils of evening primrose (Oenothera
biennis) and borage (Borago officinalis) may reduce seizure
thresholds and should not be given with anticonvulsants. Echinacea should not be
administered in conjunction with immunosuppressants (e.g., cyclosporine) (Miller
Traditional uses of herbs are often confirmed by research; however,
pharmacological analysis of active constituents is complicated by the fact that
active plant ingredients are often multi-chemical in nature, and herbal
treatments may be given in combinations for which the biomolecular interactions
are unknown (Barrett et al. 1999). These challenges are illustrated by studies
of two traditional menopause remedies: black cohosh (Cimicifuga racemosa)
and dong quai (Angelica sinensis). Studies have indicated that black
cohosh, through the synergistic effect of at least three compounds, selectively
suppresses luteinizing hormone (LH) secretions with no effect on follicular
stimulating hormone (FSH) (Duker et al. 1991). Animal studies of black cohosh
demonstrate no estrogenic activity. Black cohosh is now thought to modulate the
pituitary and LH release, thereby decreasing the fluctuations in the levels of
endogenous estrogen rather than influencing the actual level of estrogen
(Einer-Jensen et al. 1996). Dong quai has been used extensively in Traditional
Chinese Medicine for treatment of menstrual and menopausal discomfort. A
double-blind, randomized, placebo-controlled clinical trial evaluating the
estrogenic effects of dong quai in post-menopausal women found no statistically
significant differences in menopausal outcomes between dong quai and placebo
groups. Because dong quai is typically used in combination with synergistic
herbs in Traditional Chinese Medicine, the investigators conceded that
additional studies need to be done on this important herb (Hirata et al. 1997).
Very few studies have been performed evaluating the efficacy of herbalism as
it is generally practiced, i.e., administering combinations of herbs rather than
a single herb or active agent (Vickers and Zollman 1999).
As herbal medicine becomes more mainstream, there is an urgent need for a
thorough understanding of its applications and contraindications. The German
Commission E, established in 1978, compiled over 300 monographs on the most
commonly prescribed phytomedicines, based on pharmacological information and
clinical evidence. These monographs summarize available data and provide
guidelines on dosing and efficacy. An expanded American version of the
Commission E monographs, published in 2000, includes over 100 of the most
commonly prescribed herbs in the United States along with drug interactions and
potential hazards (Blumenthal et al. 2000).
While there is a movement to analyze herbs and conduct research regarding the
efficacy and safety of phytomedicines, the appropriate regulation of those herbs
in the United States has fallen far behind. Until the passage of the Dietary
Supplement Health and Education Act (DSHEA) of 1994, the FDA had not permitted
the labeling and packaging of herbs to include information on dosage or
indication. DSHEA reclassified herbs as dietary supplements that may be marketed
with suggested dosages and statements about the product's probable physiologic
effects. Although a step in the right direction, DSHEA falls short in several
areas: no premarket testing for safety or efficacy is required, manufacturing
need not be standardized, no direct claims regarding specific diseases or
conditions may be made, and FDA approval is not required. While DSHEA protected
the legal status of over-the-counter herbal products, it has done little to
dispel the confusion and misinformation around herbal use, safety, and efficacy
|Training, Certification, and
There are numerous classifications of herbalists, including professional
herbalists (who learn their trade through formalized education or
apprenticeship) and lay herbalists. Still others learn herbal medicine through
traditional medical systems, such as Ayurvedic medicine, Traditional Chinese
Medicine, and naturopathic medicine (Meserole 1996). Medical herbalists in the
United Kingdom complete a four-year program and receive at least 500 hours of
supervised clinical practice and training in nutrition, pharmacology,
pharmacognosy, botany, and basic sciences. Upon completion of the program,
graduates receive a B.Sc. degree in herbal medicine and become members of the
National Institute of Medical Herbalists (NIMH) (Vickers and Zollman 1999).
For additional information regarding phytomedicine research, the following
resources are available:
Blumenthal M, Busse WR, Goldberg A, et al., eds. The Complete German
Commission E Monographs. Boston, Mass: Integrative Medicine Communications;
Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded
Commission E Monographs. Newton, Mass: Integrative Medicine Communications;
World Health Organization (WHO). WHO Monographs on Selected Medicinal
Plants, Vol. 1. Geneva: World Health Organization; 1999.
The American Botanical Council: www.herbalgram.org/.
The National Center for Complementary and Alternative Therapy:
Phytochemical and Ethnobotanical Databases: www.ars-grin.gov/duke/.
Barrett B, Kiefer D, Rabago D. Assessing the risks and benefits of herbal
medicine: an overview of scientific evidence. Altern Ther Health Med.
Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded
Commission E Monographs. Newton, Mass: Integrative Medicine Communications;
Braunig B, Dorn G, Knick EM. Echinacea purpurea radix for
strengthening immune response in flu-like infections [in German]. Z
Brenner R, Azbel V, Madhusoodanan S, Pawlowska M. Comparison of an extract of
Hypericum (LI 160) and sertraline in the treatment of depression: a
double-blind, randomized pilot study. Clin Ther. 2000;22(4):411-419.
Chavez ML, Chavez PI. Herbal medicine. In: Novey DW, ed. Clinician's
Complete Reference to Complementary and Alternative Medicine. St. Louis, Mo:
D'Epiro NW. An historical, regulatory, and medical use perspective on nine
common herbs. In: Micozzi MS, Bacchus AN, eds. The Physician's Guide to
Alternative Medicine. Atlanta, Ga: American Health Consultants;
Donath F, Quispe S, Diefenbach K, Maurer A, Fietze I, Roots I. Critical
evaluation of the effect of valerian extract on sleep structure and sleep
quality. Pharmacopsychiatry. 2000;33(2):47-53.
Duker E, Kopanski L, Jarry H, Wuttke W. Effects of extracts from
Cimicifuga racemosa on gonadotropin release in menopausal women and
ovariectomized rats. Planta Med. 1991;57(5):420-424.
Einer-Jensen N, Zhao J, Andersen KP, Kristoffersen K. Cimicifuga and
Melbrosia lack oestrogenic effects in mice and rats. Maturitas.
Ernst E. Herbal medications for common ailments in the elderly. Drugs
Hirata JD, Swiersz LM, Zell B, Small R, Ettinger B. Does dong quai have
estrogenic effects in postmenopausal women? A double-blind, placebo-controlled
trial. Fertil Steril. 1997;68(6):981-986.
Le Bars PL, Katz MM, Berman N, Itil TM, Freedman AM, Schatzberg AF. A
placebo-controlled, double-blind, randomized trial of an extract of Ginkgo
biloba for dementia. North American EGb Study Group. JAMA.
Linde K, Mulrow CD. St. John's wort for depression (Cochrane Review). In:
The Cochrane Library, Issue 3, 2000. Oxford: Update Software.
McIntyre M. A review of the benefits, adverse events, drug interactions, and
safety of St. John's wort (Hypericum perforatum): the implications with
regard to the regulation of herbal medicines. J Altern Complement Med.
Meserole L. Western herbalism. In: Micozzi MS, ed. Fundamentals of
Complementary and Alternative Medicine. New York, NY: Churchill Livingstone;
Miller LG. Herbal medicinals: selected clinical considerations focusing on
known or potential drug-herb interactions. Arch Intern Med.
Schoeneberger D. The influence of immune-stimulating effects of pressed juice
from Echinacea purpurea on the course and severity of colds [in
German]. Forum Immunologie. 1992;8:2-12.
Vickers A, Zollman C. Herbal medicine. BMJ.
Volz HP, Kieser M. Kava-kava extract WS 1490 versus placebo in anxiety
disorders—a randomized placebo-controlled 25-week
outpatient trial. Pharmacopsychiatry. 1997;30(1):1-5.
Woelk H, Burkard G, Grunwald J. Benefits and risks of the Hypericum
extract LI 160: drug monitoring study with 3250 patients. J Geriatr
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Woelk H, Kapoula O, Lehrl S, et al. Treatment of anxiety patients. Kava
special extract WS 1490 in anxiety patients is comparable to the benzodiazepine
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Copyright © 2007 Drugs Area
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information relating to general principles
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interactions, and contraindications before administering any drug, herb, or
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