The
World Health Organization (WHO) estimates that 80 percent of the population of some Asian and African countries presently uses herbal medicine for some aspect of primary health care. Some
prescription drugs have a basis as herbal remedies, including
artemisinin,
digitalis,
quinine and
taxanes.
Regulatory review In 2015, the
Australian Government's Department of Health published the results of a review of alternative therapies that sought to determine if any were suitable for being covered by
health insurance; herbalism was one of 17 topics evaluated for which no clear evidence of effectiveness was found. Establishing guidelines to assess the safety and efficacy of herbal products, the
European Medicines Agency provided criteria in 2017 for evaluating and grading the quality of clinical research in preparing monographs about herbal products. In the United States, the
National Center for Complementary and Integrative Health of the
National Institutes of Health funds clinical trials on herbal compounds, provides fact sheets evaluating the safety, potential effectiveness and side effects of many plant sources, and maintains a registry of clinical research conducted on herbal products. According to
Cancer Research UK as of 2015, "there is currently no strong evidence from studies in people that herbal remedies can treat, prevent or cure cancer".
Prevalence of use The use of herbal remedies is more prevalent in people with
chronic diseases, such as cancer,
diabetes,
asthma, and
end-stage kidney disease. Multiple factors such as gender, age, ethnicity, education and social class are also shown to have associations with the prevalence of herbal remedy use.
Herbal preparations '' being packed into a steam
distillation unit to gather its
essential oil There are many forms in which herbs can be administered, the most common of which is a liquid consumed as a herbal tea or a (possibly diluted) plant extract. Tinctures are usually obtained by combining pure ethanol (or a mixture of pure ethanol with water) with the herb. A completed tincture has an ethanol percentage of at least 25% (sometimes up to 90%). Non-alcoholic tinctures can be made with glycerin, but it is believed to be less absorbed by the body than alcohol based tinctures and has a shorter shelf life. Herbal wine and
elixirs are alcoholic extracts of herbs, usually with an ethanol percentage of 12–38%. of
Marrakesh, Morocco Many herbs are applied topically to the skin in a variety of forms.
Essential oil extracts can be applied to the skin, usually diluted in a carrier oil. Many essential oils can burn the skin or are simply too high dose used straight; diluting them in olive oil or another food grade oil such as almond oil can allow these to be used safely as a topical.
Salves, oils,
balms, creams, and lotions are other forms of topical delivery mechanisms. 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.
Inhalation, as in
aromatherapy, can be used as a treatment.
Safety '' has been used in Ayurveda for various treatments, but contains
alkaloids, such as
atropine and
scopolamine, which may cause severe toxicity. It is a popular misconception that herbal medicines are safe and side-effect free. Consumption of herbs may cause
adverse effects. Furthermore, "adulteration, inappropriate formulation, or lack of understanding of plant and drug interactions have led to adverse reactions that are sometimes life threatening or lethal." Proper double-blind clinical trials are needed to determine the safety and efficacy of each plant before medical use. Although many consumers believe that herbal medicines are safe because they are natural, herbal medicines and synthetic drugs may interact, causing toxicity to the consumer. Herbal remedies can also be dangerously contaminated, and herbal medicines without established efficacy, may unknowingly be used to replace prescription medicines. 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, and consequently professional herbalists avoid the use of licorice where they recognize that this may be a risk. Black cohosh has been implicated in a case of liver failure. Few studies are available on the safety of herbs for pregnant women, and one study found that use of complementary and alternative medicines is associated with a 30% lower ongoing pregnancy and live birth rate during fertility treatment. Examples of herbal treatments with likely cause-effect relationships with adverse events include
aconite (which is often a legally restricted herb),
Ayurvedic remedies,
broom,
chaparral, Chinese herb mixtures,
comfrey, herbs containing certain flavonoids,
germander,
guar gum,
liquorice root, and
pennyroyal. Examples of herbs that may have long-term adverse effects include
ginseng, the endangered herb
goldenseal,
milk thistle,
senna,
aloe vera juice,
buckthorn bark and berry,
cascara sagrada bark,
saw palmetto,
valerian,
kava (which is banned in the European Union),
St. John's wort,
khat,
betel nut, the restricted herb
ephedra, and
guarana. 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, just as a customer should inform a herbalist of their consumption of actual prescription and other medication. For example, dangerously low blood pressure may result from the combination of a 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 much drug metabolism. In a 2018 study, the FDA identified active
pharmaceutical additives in over 700 analyzed dietary supplements sold as "herbal", "natural" or "traditional". The undisclosed additives included "unapproved antidepressants and designer steroids", as well as
prescription drugs, such as
sildenafil or
sibutramine.
Labeling accuracy Researchers at the
University of Adelaide found in 2014 that almost 20 percent of herbal remedies surveyed were not registered with the
Therapeutic Goods Administration, despite this being a condition for their sale. They also found that nearly 60 percent of products surveyed had ingredients that did not match what was on the label. Out of 121 products, only 15 had ingredients that matched their TGA listing and packaging. Twenty-four products were tested by
DNA barcoding as part of the investigation, with all but five containing DNA that did not match the product labels.
Practitioners of herbalism ''. In some countries, formalized training and minimum education standards exist for herbalists, although these are not necessarily uniform within or between countries. In Australia, for example, the self-regulated status of the profession (as of 2009) resulted in variable standards of training, and numerous loosely formed associations setting different educational standards. One 2009 review concluded that regulation of herbalists in Australia was needed to reduce the risk of interaction of herbal medicines with
prescription drugs, to implement clinical guidelines and prescription of herbal products, and to assure self-regulation for protection of public health and safety. In the United States, according to the American Herbalist Guild, "there is currently no licensing or certification for herbalists in any state that precludes the rights of anyone to use, dispense, or recommend herbs." However, there are U.S. federal restrictions for marketing herbs as cures for medical conditions, or essentially practicing as an unlicensed physician.
United States herbalism fraud Over the years 2017–2021, the
US Food and Drug Administration (FDA) issued
warning letters to numerous herbalism companies for illegally marketing products under "conditions that cause them to be drugs under section 201(g)(1) of the Act [21 U.S.C. § 321(g)(1)], because they are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease and/or intended to affect the structure or any function of the body" when no such evidence existed. During the
COVID-19 pandemic, the FDA and US
Federal Trade Commission issued
warnings to several hundred American companies for promoting false claims that herbal products could prevent or treat
COVID-19 disease.
Government regulations The
World Health Organization (WHO), the specialized agency of the United Nations (UN) that is concerned with international public health, published
Quality control methods for medicinal plant materials in 1998 to support WHO Member States in establishing quality standards and specifications for herbal materials, within the overall context of quality assurance and control of herbal medicines. In the European Union (EU), herbal medicines are regulated under the
Committee on Herbal Medicinal Products. In the United States, herbal remedies are regulated
dietary supplements by the
Food and Drug Administration (FDA) under
current good manufacturing practice (cGMP) policy for dietary supplements. Manufacturers of products falling into this category are not required to prove the safety or efficacy of their product so long as they do not make 'medical' claims or imply uses other than as a 'dietary supplement', though the FDA may withdraw a product from sale should it prove harmful. Canadian regulations are described by the Natural and Non-prescription Health Products Directorate which requires an eight-digit Natural Product Number or Homeopathic Medicine Number on the label of licensed herbal medicines or dietary supplements. Some herbs, such as
cannabis and
coca, are outright banned in most countries though coca is legal in most of the South American countries where it is grown. The
Cannabis plant is used as a herbal
medicine, and as such is
legal in some parts of the world. Since 2004, the sales of
ephedra as a dietary supplement is prohibited in the United States by the FDA, and subject to Schedule III restrictions in the United Kingdom.
Scientific criticism Herbalism has been criticized as a potential "
minefield" of unreliable product quality, safety hazards, and the potential for misleading health advice. Globally, there are no standards across various herbal products to authenticate their contents, safety or efficacy, and there is generally an absence of high-quality scientific research on product composition or effectiveness for anti-disease activity. Presumed claims of therapeutic benefit from herbal products, without rigorous evidence of efficacy and safety, receive skeptical views by scientists. may erode
consumer confidence about services and products. ==Paraherbalism==