Herbalism

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Herbalism is a traditional medicinal or folk medicine practice based on the use of plants and plant extracts. Herbalism is also known as botanical medicine, medicinal botany,(a neologism coined by Dr. K. Seshagirirao, University of Hyderabad, India) medical herbalism, herbal medicine, herbology, and phytotherapy. Sometimes the scope of herbal medicine is extended to include fungi and bee products, as well as minerals, shells and certain animal parts.Many plants synthesize substances that are useful to the maintenance of health in humans and other animals. These include aromatic substances, most of which are phenols or their oxygen-substituted derivatives such as tannins. Many are secondary metabolites, of which at least 12,000 have been isolated — a number estimated to be less than 10% of the total. In many cases, these substances (particularly the alkaloids) serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Many of the herbs and spices used by humans to season food yield useful medicinal compounds.

Anthropology of herbalism

People on all continents have used hundreds to thousands of indigenous plants for treatment of ailments since prehistoric times. There is evidence from the Shanidar Cave in Iraq that suggests Neanderthals living 60,000 years ago used medicinal plants. A body that was unearthed there had been buried with eight species of plants which are still widely used in ethnomedicine around the world.Medicinal plants in a Middle Paleolithic grave Shanidar IV?, Lietava J., J Ethnopharmacol. 1992 Jan;35(3):263-6., PMID 1548898 The first generally accepted use of plants as healing agents was depicted in the cave paintings discovered in the Lascaux caves in France, which have been radiocarbon-dated to between 13,000-25,000 BCE. Medicinal herbs were found in the personal effects of an "Ice man," whose body was frozen in the Swiss Alps for more than 5,300 years, which appear to have been used to treat the parasites found in his intestines.5300 years ago, the Ice Man used natural laxatives and antibiotics, Capasso L., Lancet. 1998;352:1864, PMID 9851424. Anthropologists theorize that animals evolved a tendency to seek out bitter plant parts in response to illness. This behavior arose because bitterness is an indicator of secondary metabolites. The risk benefit ratio favored animals and protohumans that were inclined to experiment in times of sickness. Over time, and with insight, instinct, and trial-and-error, a base of knowledge would have been acquired within early tribal communities. As this knowledge base expanded over the generations, the specialized role of the herbalist emerged. The process would likely have occurred in varying manners within a wide diversity of cultures.Indigenous healers often claim to have learned by observing that sick animals change their food preferences to nibble at bitter herbs they would normally reject. Field biologists have provided corroborating evidence based on observation of diverse species, such as chimpanzees, chickens, sheep and butterflies. Lowland gorillas take 90% of their diet from the fruits of Aframomum melegueta, a relative of the ginger plant, that is a potent antimicrobial and apparently keeps shigellosis and similar infections at bay.Wild Health: How Animals Keep Themselves Well and What We Can Learn From Them, Cindy Engel, Houghton Mifflin, 2002 Researchers from Ohio Wesleyan University found that some birds select nesting material rich in antimicrobial agents which protect their young from harmful bacteriaJan Ichida, Proceedings of the 104th General Meeting of the American Society for Microbiology. reported in Birds use herbs to protect their nests, BJS, Science Blog, Wed, 2004-05-26. Sick animals tend to forage plants rich in secondary metabolites, such as tannins and alkaloids. Since these phytochemicals often have antiviral, antibacterial, antifungal and antihelminthic properties, a plausible case can be made for self-medication by animals in the wild.Some animals have digestive systems especially adapted to cope with certain plant toxins. For example, the koala can live on the leaves and shoots of the eucalyptus, a plant that is dangerous to most animals. A plant that is harmless to a particular animal may not be safe for humans to ingest. A reasonable conjecture is that these discoveries were traditionally collected by the medicine people of indigenous tribes, who then passed on safety information and cautions.

Herbs in history

In the written record, the study of herbs dates back over 5,000 years to the Sumerians, who described well-established medicinal uses for such plants as laurel, caraway, and thyme. The first known Chinese herb book (or herbal), dating from about 2700 B.C., lists 365 medicinal plants and their uses - including ma-Huang, the shrub that introduced the drug ephedrine to modern medicine. The Egyptians of 1000 B.C. are known to have used garlic, opium, castor oil, coriander, mint, indigo, and other herbs for medicine and the Old Testament also mentions herb use and cultivation, including mandrake, vetch, caraway, wheat, barley, and rye.Like their predecessors, the ancient Greeks and Romans made medicinal use of plants. Greek and Roman medicinal practices, as preserved in the writings of Hippocrates and - especially - Galen, provided the patterns for later western medicine. Hippocrates advocated the use of a few simple herbal drugs - along with fresh air, rest, and proper diet. Galen, on the other had, recommended large doses of more or less complicated drug mixtures - including plant, animal, and mineral ingredients. The Greek physician compiled the first European treatise on the properties and uses of medicinal plants, De Materia Medica. In the first century AD, Dioscorides wrote a compendium of more that 500 plants that remained an authoritative reference into the seventeenth century. Similarly important for herbalists and botanists of later centuries was the Greek book that founded the science of botany, Theophrastus’ Historia Plantarum, written in the fourth century B.C. The uses of plants for medicine and other purposes changed little during the Middle Ages. The early Christian church discouraged the formal practice of medicine, preferring faith healing; but many Greek and Roman writings on medicine, as on other subjects, were preserved by diligent hand copying of manuscripts in monasteries. The monasteries thus tended to become local centers of medical knowledge, and their herb gardens provided the raw materials for simple treatment of common disorders. At the same time, folk medicine in the home and village continues uninterrupted, supporting numerous wandering and settled herbalists. Among these were the “wise-women,” who prescribed herbal remedies often along with spells and enchantments. It was not until the later Middle Ages that women who were knowledgeable in herb lore became the targets of the witch hysteria. One of the most famous women in the herbal tradition was Hildegard of Bingen. A twelfth century Benedictine nun, she wrote a medical text called Causes and Cures.Medical schools began to return in the eleventh century, teaching Galen’s system. At the time, the Arabic world was more advanced in science than Europe. As a trading culture, the Arabs had access to plant material from distant places such as China and India. Herbals, medical texts and translations of the classics of antiquity filtered in from east to west. Alongside the university system, folk medicine continued to thrive. Plants were burdened with a mass of both pagan and Christian superstition that often was more important than their actual properties. The continuing importance of herbs for the centuries following the Middle Ages is indicated by the hundreds of herbals published after the invention of printing in the fifteenth century. Theophrastus’ Historia Plantarum was one of the first books to be printed, and Dioscorides’ De Materia Medica was not far behind. The fifteenth, sixteenth, and seventeenth centuries were the great age of herbals, many of them available for the first time in English and other languages rather than Latin or Greek. The first herbal to be published in English was the anonymous Grete Herball of 1526. The two best-known herbals in English wereThe Herball or General History of Plants (1597) by John Gerard and The English Physician Enlarged (1653) by Nicholas Culpeper. Gerard’s text was basically a pirated translation of a book by the Belgian herbalist Dodoens and his illustrations came from a German botanical work. The original edition contained many errors due to faulty matching of the two parts. Culpeper’s blend of traditional medicine with astrology, magic, and folklore was ridiculed by the physicians of his day yet his book - like Gerard’s and other herbals - enjoyed phenomenal popularity. The Age of Exploration and the Columbian Exchange introduced new medicinal plants to Europe. The Badianus Manuscript was an illustrated Aztec herbal translated into Latin in the 16th century.The second millenium, however, also saw the beginning of a slow erosion of the pre-eminent position held by plants as sources of therapeutic effects. This began with the introduction of the physician, the introduction of active chemical drugs (like arsenic, copper sulfate, iron, mercury, and sulfur), followed by the rapid development of chemistry and the other physical sciences, led increasingly to the dominance of chemotherapy - chemical medicine - as the orthodox system of the twentieth century.

Role of herbal medicine in modern human society

The use of herbs to treat disease is almost universal among non-industrialized societies. A number of traditions came to dominate the practice of herbal medicine at the end of the twentieth century:
  • The herbal medicine system, based on Greek and Roman sources
  • The Ayurvedic medicine system from India
  • Chinese herbal medicine (Chinese herbology)
  • Unani-Tibb medicine
  • Shamanic Herbalism
    • Many of the pharmaceuticals currently available to physicians have a long history of use as herbal remedies, including opium, aspirin, digitalis, and quinine. The World Health Organization (WHO) estimates that 80 percent of the world's population presently uses herbal medicine for some aspect of primary health care. Herbal medicine is a major component in all traditional medicine systems, and a common element in Ayurvedic, homeopathic, naturopathic, traditional Chinese medicine, and Native American medicine. The use of, and search for, drugs and dietary supplements derived from plants have accelerated in recent years. Pharmacologists, microbiologists, botanists, and natural-products chemists are combing the Earth for phytochemicals and leads that could be developed for treatment of various diseases. In fact, according to the World Health Organisation, approximately 25% of modern drugs used in the United States have been derived from plants.
  • Three quarters of plants that provide active ingredients for prescription drugs came to the attention of researchers because of their use in traditional medicine.
  • Among the 120 active compounds currently isolated from the higher plants and widely used in modern medicine today, 80 percent show a positive correlation between their modern therapeutic use and the traditional use of the plants from which they are derived.
  • More than two thirds of the world's plant species - at least 35,000 of which are estimated to have medicinal value - come from the developing countries.
  • At least 7,000 medical compounds in the modern pharmacopoeia are derived from plants

    • Biological background

    All plants produce chemical compounds as part of their normal metabolic activities. These include primary metabolites, such as sugars and fats, found in all plants, and secondary metabolites found in a smaller range of plants, some useful ones found only in a particular genus or species. Pigments harvest light, protect the organism from radiation and display colors to attract pollinators. Many common weeds have medicinal properties . The functions of secondary metabolites are varied. For example, some secondary metabolites are toxins used to deter predation, and others are pheremones used to attract insects for pollination. Phytoalexins protect against bacterial and fungal attacks. Allelochemicals inhibit rival plants that are competing for soil and light.Plants upregulate and downregulate their biochemical paths in response to the local mix of herbivores, pollinators and microorganisms. The chemical profile of a single plant may vary over time as it reacts to changing conditions. It is the secondary metabolites and pigments that can have therapeutic actions in humans and which can be refined to produce drugs.Plants synthesize a bewildering variety of phytochemicals but most are derivatives of a few biochemical motifs.
  • Alkaloids contain a ring with nitrogen. Many alkaloids have dramatic effects on the central nervous system. Caffeine is an alkaloid that provides a mild lift but the alkaloids in datura cause severe intoxication and even death.
  • Phenolics contain phenol rings. The anthocyanins that give grapes their purple color, the isoflavones, the phytoestrogens from soy and the tannins that give tea its astringency are phenolics.
  • Turpenoids are built up from terpene building blocks. Each terpene consists of two paired isoprenes. The names monoterpenes, sesquiterpenes, diterpenes and triterpenes are based on the number of isoprene units. The fragrance of rose and lavender is due to monoterpenes. The carotenoids produce the reds, yellows and oranges of pumpkin, corn and tomatoes.
  • Glycosides consist of a glucose moiety attached to an aglycone. The aglycone is a molecule that is bioactive in its free form but inert until the glycoside bond is broken by water or enzymes. This mechanism allows the plant to defer the availability of the molecule to an appropriate time, similar to a safety lock on a gun. An example is the cyanoglycosides in cherry pits that release toxins only when bitten by a herbivore.
    • The word drug itself comes from the Swedish word "druug", which means 'dried plant'. Some examples are inulin from the roots of dahlias, quinine from the cinchona, morphine and codeine from the poppy, and digoxin from the foxglove. The active ingredient in willow bark, once prescribed by Hippocrates, is salicin, or salicylic acid. The discovery of salicylic acid, also known as "acetylsalicylic acid", would eventually lead to the development of "aspirin" when it was isolated from a plant known as meadowsweet. The word aspirin comes from an abbreviation of meadowsweet's Latin genus Spiraea, with an additional "A" at the beginning to acknowledge acetylation, and "in" was added at the end for easier pronunciation. "Aspirin" was originally a brand name, and is still a protected trademark in some countries. This medication was patented by Bayer AG.

    Herbal philosophy

    Since herbalism is such a diverse field few generalizations apply universally. Nevertheless a rough consensus can be inferred.Most herbalists concede that pharmaceuticals are more effective in emergency situations where time of the essence. An example would be where a patient had elevated blood pressure that posed immanent danger. However they claim that over the long term herbs can help the patient resist disease and in addition provide nutritional and immunological support that pharmaceuticals lack. They view their goal as prevention as well as cure.Herbalists tend to use parts of plants, such as the roots or leaves but not isolate particular phytochemicals. Pharmaceutical medicine prefers single ingredients on the grounds that dosage can be more easily quantified. Herbalists state that the Drug synergism of the combined substances enhances the efficacy and dilutes toxicity. Herbalists reject the notion of a single active ingredient. They argue that the different phytochemicals present in many herbs will interact to enhance the therapeutic effects of the herb. Furthermore, they argue that a single ingredient may contribute to multiple effects. Herbalists state that combined effect cannot be produced without administering an extract from the herb, arguing that phytochemical interactions and trace components may alter the drug response in ways that cannot currently be replicated with a combination of a few putative active ingredients. Researchers note that clinical trials may be used to investigate the efficacy of a particular herbal preparation, provided the formulation of that herb is consistent. In specific cases the claims of synergy and multifunctionality have been supported by science. The open question is how widely both can be generalized.Herbalists would argue that cases of synergy can be widely generalized, on the basis of a postulated evolutionary history. Herbalists state that plants are subject to similar selection pressures as humans, believing that they must develop resistance to threats such as radiation, ROS and microbial attack in order to survive. They argue that optimal chemical defenses have been selected for and have thus developed over millions of years. According to herbalists human diseases are multifactorial and may be treated by consuming the chemical defences that they believe to be present in herbs. Bacteria, inflammation, nutrition and ROS may all play a role in arterial disease. Herbalists claim a single herb may simultaneously address several of these factors. Likewise a factor such as ROS may underly more than one condition. In short herbalists view their field as the study of a web of relationships rather than a quest for single cause and a single cure for a single condition.In selecting herbal treatments herbalists may use forms of information that are not applicable to pharmacists. Because herbs can moonlight as vegetables, teas or spices they have a huge consumer base and large-scale epidemiological studies become feasible. Ethnobotanical studies are another source of information. For example, when indigenous peoples from geographically dispersed areas use closely related herbs for the same purpose that is taken as supporting evidence for its efficacy. Herbalists contend that historical medical records and herbals are underutilized resources. They favor the use of convergent information in assessing the medical value of plants. An example would be when in-vitro activity is consistent with traditional use.Certain strains of herbalism rely on sources that would be widely considered unreliable and would not be accepted in a scientifically oriented herbal journal. These include astrology, the Bible, intuition, dreams, “plant spirits”, etc.

    Popularity

    A survey released in May 2004 by the National Center for Complementary and Alternative Medicine focused on who used complementary and alternative medicines (CAM), what was used, and why it was used. The survey was limited to adults, aged 18 years and over during 2002, living in the United States. According to this survey, herbal therapy, or use of natural products other than vitamins and minerals, was the most commonly used CAM therapy (18.9%) when all use of prayer was excluded. (See table 1 on page 8).More Than One-Third of U.S. Adults Use Complementary and Alternative Medicine Press release, May 27, 2004. National Center for Complementary and Alternative MedicineHerbal remedies are very common in Europe. In Germany, herbal medications are dispensed by apothecaries (e.g., Apotheke). Prescription drugs are sold alongside essential oils, herbal extracts, or herbal teas. Herbal remedies are seen by some as a treatment to be preferred to chemical medications which have been industrially produced.In the United Kingdom, the training of medical herbalists is done by state funded Universities. For example, Bachelor of Science degrees in herbal medicine are offered at Universities such as University of East London, Middlesex University, University of Central Lancashire, University of Westminster, University of Lincoln and Napier University in Edinburgh at the present.

    Types of herbal medicine systems

    Use of medicinal plants can be as informal as, for example, culinary use or consumption of an herbal tea or supplement, although the sale of some herbs considered dangerous is often restricted to the public. Sometimes such herbs are provided to professional herbalists by specialist companies. Many herbalists, both professional and amateur, often grow or "wildcraft" their own herbs.Some researchers trained in both western and traditional Chinese medicine have attempted to deconstruct ancient medical texts in the light of modern science. One idea is that the yin-yang balance, at least with regard to herbs, corresponds to the pro-oxidant and anti-oxidant balance. This interpretation is supported by several investigations of the {ORAC ratings of various yin and yang herbs.Eclectic medicine came out of the vitalist tradition, similar to physiomedicalism and bridged the European and Native American traditions. Cherokee medicine tends to divide herbs into foods, medicines and toxins and to use seven plants in the treatment of disease, which is defined with both spiritual and physiological aspects, according to Cherokee herbalist David Winston.[http://oneearthherbs.squarespace.com/safety-regulation/ Safety & Regulation--Whos Watching the Herbal Store?''], Tillotson Institute of Natural HealthIn India, Ayurvedic medicine has quite complex formulas with 30 or more ingredients, including a sizable number of ingredients that have undergone "alchemical processing", chosen to balance "Vata", "Pitta" or "Kapha."http://oneearthherbs.squarespace.com/language-of-herbs/In addition there are more modern theories of herbal combination like William LeSassier's triune formula which combined Pythagorean imagery with Chinese medicine ideas and resulted in 9 herb formulas which supplemented, drained or neutrally nourished the main organ systems affected and three associated systems. His system has been taught to thousands of influential American herbalists through his own apprenticeship programs during his lifetime, the William LeSassier ArchiveWilliam LeSassier Archive website and the David Winston Center for Herbal StudiesDavid Winston Center for Herbal Studies website

    Routes of administration

    There are many forms in which herbs can be administered, these include:
  • Tinctures (alcoholic extracts of herb, such as echinacea extract)
  • Tisanes (hot-water extracts of herb, such as chamomile)
  • Topicals:
  • Essential oils- application of essential oil extracts, usually diluted in a carrier oil (many essential oils can burn the skin or are simply too high dose used straight- diluting in olive oil or another food grade oil can allow these to be used safely as a topical).
  • Salves, oils, creams and lotions- Most topical applications are oil extractions of herbs. Taking a food grade oil and soaking herbs in it for anywhere from weeks to months allows certain phytochemicals to be extracted into the oil. This oil can then be made into salves, creams, lotions, or simply used as an oil for topical application. Many massage oils, antibacterial salves and wound healing compounds are made this way.
  • Poultices and compresses- One can also make a poultice or compress using whole herb (or the appropriate part of the plant) usually crushed or dried and re hydrated with a small amount of water and then applied directly in a bandage, cloth or just as is.
  • Whole-herb consumption- Eating vegetables easily fits in this category, all of the vitamins, minerals and antioxidants are phytochemicals that we are accessing through our diet. There are clearly some whole herbs that we consume that are more powerful than others. Shiitake mushrooms boost the immune system and taste great so they are fabulous in soups or other food preparations for the cold and flu season. Garlic lowers cholesterol, improves blood flow, fights bacteria, viruses and yeast.
  • Inhalation as in aromatherapy can be used as a mood changing treatment, to fight a sinus infection or cough, or to cleanse the skin on a deeper level (steam not direct inhalation here).

    • Examples of plants used as medicine

    Few herbal remedies have conclusively demonstrated any positive effect on humans. Many of the studies cited refer to animal model investigations or in-vitro assays and therefore cannot provide more than weak supportive evidence.
  • Artichoke and several other plants may reduce total serum cholesterol levels in preliminary studies.
  • Bilberry#Medicinal uses
  • Bitter melon#Medicinal uses
  • Black cohosh and other plants that contain phytoestrogens (plant molecules with estrogen activity) have some benefits for treatment of symptoms resulting from menopause.
  • Butterbur#Medicinal uses (Petasites )
  • Calendula#medicinal effects
  • Cranberry#Health benefits
  • Echinacea extracts may limit the length and severity of rhinovirus colds; however, the appropriate dosage levels, which might be higher than is available over-the-counter, require further research.
  • Elderberry may speed the recovery from type A and B influenza. However it is possibly risky in the case of avian influenza because the immunostimulatory effects may aggravate the cytokine cascade.
  • Feverfew is sometimes used to treat migraine headaches.However, many reviews of these studies show no or unclear efficacy. However a more recent RTC showed favorable results, Feverfew is not recommended for pregnant women as it may be dangerous to the fetus.
  • Garlic may lower total cholesterol levels
  • Ginger#Medical uses
  • Purified extracts of the seeds of Hibiscus sabdariffa may have some antihypertensive, antifungal and antibacterial effect. Toxicity tested low except for an isolated case of damage to the testes of a rat after prolonged and excessive consumption.
  • Milk thistle#Health benefits
  • Nigella sativa (Black cumin) has demonstrated analgesic properties in mice. The mechanism for this effect, however, is unclear. In vitro studies support antibacterial, antifungal, anticancer, anti-inflammatory and immune modulating effects.
    • However few randomized double blind studies have been published.
  • Oregano may be effective against multi-drug resistant bacteria.
  • Pawpaw can be used for insecticidal purposes (killing lice, worms).
  • Phytolacca or Pokeweed is used as a homeopathic remedy to treat many ailments. It can be applied topically or taken internally. Topical treatments have been used for acne and other ailments. It is used to treatment tonsilitis, swollen glands and weight loss.
  • Peppermint oil may have benefits for individuals with irritable bowel syndrome.
  • Pomegranate#Health benefits
  • Rauvolfia Serpentina, high risk of toxicity if improperly used, used extensively in India for sleeplessness, anxiety, and high blood pressure.
  • Salvia lavandulaefolia may improve memory
  • St. John's wort, has yielded positive results, proving more effective than a placebo for the treatment of mild to moderate depression in some clinical trials A subsequent, large, controlled trial, however, found St. John's wort to be no better than a placebo in treating depression However more recent trials have shown positive results or positive trands that failed significance. A 2004 meta-analysis concluded that the positive results can be explained by publication bias but later analyses have been more favorable.The Cochrane Database cautions that the data on St. John's wort for depression are conflicting and ambiguous.
  • Saw Palmetto can be used for BPH. Supported in some studies , failed to confirm in otherrs.
  • Shittake#Medicinal use
  • Valerian root can be used to treat insomnia. Clinical studies show mixed results and researchers note that many trials are of poor quality.
  • Vanilla#Medicinal effects
  • Lemon juice or apple cider vinegar can be used to treat acne.
  • Green tea components may inhibit growth of breast cancer cells and may heal scars faster.
  • Lemon grass can lower cholesterol.
  • Honey may reduce cholesterol. May be useful in wound healing.

    • Risks

    Standardization of purity and dosage is not mandated in the United States but even products made to the same specification may differ as a result of biochemical variations within a species of plant. Plants have chemical defense mechanisms against predators that can have adverse or lethal effects on humans. Examples of highly toxic herbs include poison hemlock and nightshade. They are not marketed to the public as herbs, because the risks are well known, partly due to a long and colorful history in Europe, associated with "sorcery", "magic" and intrigue. Although not frequent, adverse reactions have been reported for herbs in widespread use. On occasion serious untoward outcomes have been linked to herb consumption. A case of major potassium depletion has been attributed to chronic licorice ingestion. Black cohosh has been implicated in a case of liver failure.Few studies are available on the safety of herbs for pregnant women.Herbs to avoid during pregnancy, Gaia Garden websiteHerb drug interactions are a concern. In consultation with a physician, usage of herbal remedies should be clarified, as some herbal remedies have the potential to cause adverse drug interactions when used in combination with various prescription and over-the-counter pharmaceuticals.Dangerously low blood pressure may result from the combination of an herbal remedy that lowers blood pressure together with prescription medicine that has the same effect. Some herbs may amplify the effects of anticoagulants. Certain herbs as well as common fruit interfere with cytochrome P450, an enzyme critical to drug metabolism.

    Effectiveness

    The gold standard for pharmaceutical testing is repeated, large-scale, randomized, double-blind tests. Some plant products or pharmaceutical drugs derived from them are incorporated into mainstream medicine. To recoup the considerable costs of testing to the regulatory standards, the substances are patented by pharmaceutical companies and sold at a substantial profit.Most herbal traditions have developed without modern scientific controls to distinguish between the placebo effect, the body's natural ability to heal itself, and the actual benefits of the herbs themselves. Many herbs have shown positive results in in-vitro, animal model or small-scale clinical tests but many studies on herbal treatements have also found negative results. The quality of the trials on herbal remedies is highly and many trials of herbal treatments have been found to be of poor quality, with many trials lacking a intention to treat analysis or a comment on whether blinding was successful. The few randomized, double-blind tests that receive attention in mainstream medical publications are often questioned on methodological grounds or interpretation. Likewise, studies published in peer-reviewed medical journals such as Journal of the American Medical Association receive more consideration than those published in specialized herbal journals. This preference may be due to the possibility of location bias for such trials. One study found that non-impact factor alternative medicine journals published more studies with positive results than negative results and that trials finding positive results were of lower quality than trials finding negative results. High impact factor mainstream medical journals, on the other hand, published equal numbers of trials with positive and negative results. In high impact journals, trials finding positive results were also found to have lower quality scores than trials finding negative results. Another study found studies of phyomedicine to have superior quality to matched studies of pharmaceuticals. However, this study used a matched pair design and excluded all herbal trials that were not controlled, did not use a placebo or did not use random or quasi random assignment.Herbalists criticize mainstream studies on the grounds that they make insufficient use of historical use. They maintain that tradition can guide the selection of factors such as optimal dose, species, time of harvesting and target population.Dosage is in general an outstanding issue for herbal treatments: while most conventional medicines are heavily tested to determine the most effective and safest dosages (especially in relation to things like body weight, drug interactions, etc.), there are few established dosage standards for various herbal treatments on the market. Furthermore, herbal medicines taken in whole form cannot generally guarantee a consistent dosage or drug quality (since certain samples may contain more or less of a given active ingredient.Several methods of standardization may be applied to herbs. One is the ratio of raw materials to solvent. However different specimens of even the same plant species may vary in chemical content. Another method is standardization on a signal chemical.

    Evidence-based herbal medicine

    In 2004 the U.S. National Center for Complementary and Alternative Medicine of the National Institutes of Health began funding clinical trials into the effectiveness of herbal medicine.Herbal Medicine, NIH Institute and Center Resources, National Center for Complementary and Alternative Medicine, National Institutes of Health.Surveys of a scientific approach to herbal medicine can be found in the books Evidence-based herbal medicine,"Evidence-based herbal medicine" edited by Michael Rotblatt, Irwin Ziment; Philadelphia: Hanley & Belfus, 2002 and Herbal and traditional medicine: molecular aspects of health."Herbal and traditional medicine: molecular aspects of health", edited by Lester Packer, Choon Nam Ong, Barry Halliwell; New York: Marcel Dekker, 2004.

    Name confusion

    The common names of herbs (folk taxonomy) may not reflect differences in scientific taxonomy, and the same (or a very similar) common name might group together different plant species with different effects. For example, in 1993 in Belgium, a formula created by medical doctors including some Traditional Chinese medicine (TCM) herbs for weight loss, one herb (Stephania tetrandra) was swapped for another (Aristolochia fangchi) whose name in Chinese was extremely similar but which contained higher levels of a renal toxin, aristolochic acid; this quid pro quo resulted in 105 cases of kidney damage. Note that neither herb used in a TCM context would be used for weight loss or given for long periods of time. In Chinese medicine these herbs are used for certain forms of acute arthritis and edema. Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble. Chinese Herbal Medicine: Materia Medica, Third Edition. 2004: 1054-1055 Vanherweghem JL, Depierreux M, Tielemans C, et al. "Rapidly progressive interstitial renal fibrosis in young women: association with slimming regimen including Chinese herbs." Lancet. 1993 Feb 13;341(8842):387-91.Vanhaelen M, Vanhaelen-Fastre R, But P, Vanherweghem JL. "Identification of aristolochic acid in Chinese herbs." Lancet. 1994 Jan 15;343(8890):174. PMID 7904018

    Standards and quality control

    The issue of regulation is an area of continuing controversy in the EU and USA. At one end of the spectrum, some herbalists maintain that traditional remedies have a long history of use, and do not require the level of safety testing as xenobiotics or single ingredients in an artificially concentrated form. On the other hand, others are in favor of legally enforced quality standards, safety testing and prescription by a qualified practitioner. Some professional herbalist organizations have made statements calling for a category of regulation for herbal products. Yet others agree with the need for more quality testing but believe it can be managed through reputation without government intervention.The legal status of herbal ingredients varies by country.In the United States, most herbal remedies are regulated as dietary supplements by the Food and Drug Administration. Manufacturers of products falling into this category are not required to prove the safety or efficacy of their product, though the FDA may withdraw a product from sale should it prove harmful.US Dietary Supplement Health and Education Act of 1994The National Nutritional Foods Association, the industry's largest trade association, has run a program since 2002, examining the products and factory conditions of member companies, giving them the right to display the GMP (Good Manufacturing Practices) seal of approval on their products.[http://oneearthherbs.squarespace.com/safety-regulation/ Safety & Regulation--Whos Watching the Herbal Store?''], Tillotson Institute of Natural HealthIn the UK, herbal remedies that are bought over the counter are regulated as supplements, as in the US. However, herbal remedies prescribed and dispensed by a qualified "Medical Herbalist", after a personal consultation, are regulated as medicines. A Medical Herbalist can prescribe some herbs which are not available over the counter, covered by Schedule III of the Medicines Act. Forthcoming changes to laws regulating herbal products in the UK, are intended to ensure the quality of herbal products used.Some herbs, such as cannabis, however, are outright banned in most countries for various reasons. Since 2004, the sales of ephedra as an herbal supplement is prohibited in the United States by the FDA. FDA Issues Regulation Prohibiting Sale of Dietary Supplements Containing Ephedrine Alkaloids and Reiterates Its Advice That Consumers Stop Using These Products

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