Herbal medicine (also herbalism) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remedies, such as the anti-malarial group of drugs called artemisinin isolated from Artemisia annua, a herb that was known in Chinese medicine to treat fever. There is limited scientific evidence for the safety and efficacy of plants used in 21st century herbalism, which generally does not provide standards for purity or dosage. The scope of herbal medicine commonly includes fungal and bee products, as well as minerals, shells and certain animal parts. Herbal medicine is also called phytomedicine or phytotherapy.
Paraherbalism describes alternative and pseudoscientific practices of using unrefined plant or animal extracts as unproven medicines or health-promoting agents. Paraherbalism relies on the belief that preserving various substances from a given source with less processing is safer or more effective than manufactured products, a concept for which there is no evidence.
Archaeological evidence indicates that the use of medicinal plants dates back to the Paleolithic age, approximately 60,000 years ago. Written evidence of herbal remedies dates back over 5,000 years to the Sumerians, who compiled lists of plants. Some ancient cultures wrote about plants and their medical uses in books called herbals. In ancient Egypt, herbs are mentioned in Egyptian medical papyri, depicted in tomb illustrations, or on rare occasions found in medical jars containing trace amounts of herbs. In ancient Egypt, the Ebers papyrus dates from about 1550 BC, and covers more than 700 compounds, mainly of plant origin. The earliest known Greek herbals came from Theophrastus of Eresos who, in the 4th century BC, wrote in Greek Historia Plantarum, from Diocles of Carystus who wrote during the 3rd century BC, and from Krateuas who wrote in the 1st century BC. Only a few fragments of these works have survived intact, but from what remains, scholars noted overlap with the Egyptian herbals. Seeds likely used for herbalism were found in archaeological sites of Bronze Age China dating from the Shang dynasty (c. 1600–1046 BC). Over a hundred of the 224 compounds mentioned in the Huangdi Neijing, an early Chinese medical text, are herbs. Herbs were also commonly used in the traditional medicine of ancient India, where the principal treatment for diseases was diet. De Materia Medica, originally written in Greek by Pedanius Dioscorides (c. 40–90 AD) of Anazarbus, Cilicia, a physician and botanist, is one example of herbal writing used over centuries until the 1600s.
Modern herbal medicineEdit
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 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.
Prevalence of useEdit
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 association with prevalence of herbal remedies use.
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.
Herbal teas, or tisanes, are the resultant liquid of extracting herbs into water, though they are made in a few different ways. Infusions are hot water extracts of herbs, such as chamomile or mint, through steeping. Decoctions are the long-term boiled extracts, usually of harder substances like roots or bark. Maceration is the cold infusion of plants with high mucilage-content, such as sage or thyme. To make macerates, plants are chopped and added to cold water. They are then left to stand for 7 to 12 hours (depending on herb used). For most macerates, 10 hours is used.
Tinctures are alcoholic extracts of herbs, which are generally stronger than herbal teas. 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 extract of herbs, usually with an ethanol percentage of 12–38%. Extracts include liquid extracts, dry extracts, and nebulisates. Liquid extracts are liquids with a lower ethanol percentage than tinctures. They are usually made by vacuum distilling tinctures. Dry extracts are extracts of plant material that are evaporated into a dry mass. They can then be further refined to a capsule or tablet.
The exact composition of an herbal product is influenced by the method of extraction. A tea will be rich in polar components because water is a polar solvent. Oil on the other hand is a non-polar solvent and it will absorb non-polar compounds. Alcohol lies somewhere in between.
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.
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 are 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 (against which herbalists generally advise and rarely use), 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.
There is also concern with respect to the numerous well-established interactions of herbs and drugs. 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 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 much drug metabolism.
In a 2018 study, FDA identified active pharmaceutical additives in over 700 of 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.
A 2013 study found that one-third of herbal supplements sampled contained no trace of the herb listed on the label. The study found products adulterated with contaminants or fillers not listed on the label, including potential allergens such as soy, wheat, or black walnut. One bottle labeled as St. John's wort was found to actually contain Alexandrian senna, a laxative.
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.
In 2015, the New York Attorney General issued cease and desist letters to four major U.S. retailers (GNC, Target, Walgreens, and Walmart) who were accused of selling herbal supplements that were mislabeled and potentially dangerous. 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 herbalismEdit
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 Kingdom, the training of herbalists is done by state-funded universities offering Bachelor of Science degrees in herbal medicine. 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 fraudEdit
Over the years 2017–21, the U.S. 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 U.S. Federal Trade Commission issued warnings to several hundred American companies for promoting false claims that herbal products could prevent or treat COVID-19 disease.
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 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 an 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.
Herbalism has been criticized as a potential "minefield" of unreliable product quality, safety hazards, and 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.
Unethical practices by some herbalists and manufacturers, which may include false advertising about health benefits on product labels or literature, and contamination or use of fillers during product preparation, may erode consumer confidence about services and products.
Paraherbalism is the pseudoscientific use of extracts of plant or animal origin as supposed medicines or health-promoting agents. Phytotherapy differs from plant-derived medicines in standard pharmacology because it does not isolate and standardize the compounds from a given plant believed to be biologically active. It relies on the false belief that preserving the complexity of substances from a given plant with less processing is safer and potentially more effective, for which there is no evidence either condition applies.
Phytochemical researcher Varro Eugene Tyler described paraherbalism as "faulty or inferior herbalism based on pseudoscience", using scientific terminology but lacking scientific evidence for safety and efficacy. Tyler listed ten fallacies that distinguished herbalism from paraherbalism, including claims that there is a conspiracy to suppress safe and effective herbs, herbs can not cause harm, that whole herbs are more effective than molecules isolated from the plants, herbs are superior to drugs, the doctrine of signatures (the belief that the shape of the plant indicates its function) is valid, dilution of substances increases their potency (a doctrine of the pseudoscience of homeopathy), astrological alignments are significant, animal testing is not appropriate to indicate human effects, anecdotal evidence is an effective means of proving a substance works and herbs were created by God to cure disease. Tyler suggests that none of these beliefs have any basis in fact.
Up to 80% of the population in Africa uses traditional medicine as primary health care.
Native Americans used about 2,500 of the approximately 20,000 plant species that are native to North America.
Some researchers trained in both Western and traditional Chinese medicine have attempted to deconstruct ancient medical texts in the light of modern science. In 1972, Tu Youyou, a pharmaceutical chemist, extracted the anti-malarial drug artemisinin from sweet wormwood, a traditional Chinese treatment for intermittent fevers.
In 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 dosha. In Ladakh, Lahul-Spiti, and Tibet, the Tibetan Medical System is prevalent, also called the "Amichi Medical System". Over 337 species of medicinal plants have been documented by C.P. Kala. Those are used by Amchis, the practitioners of this medical system. The Indian book, Vedas, mentions treatment of diseases with plants.
In Indonesia, especially among the Javanese, the jamu traditional herbal medicine may have originated in the Mataram Kingdom era, some 1300 years ago. The bas-reliefs on Borobudur depict the image of people grinding herbs with stone mortar and pestle, a drink seller, an herbalist, and masseuse treating people. The Madhawapura inscription from Majapahit period mentioned a specific profession of herbs mixer and combiner (herbalist), called Acaraki. The book from Mataram dated from circa 1700 contains 3,000 entries of jamu herbal recipes, while Javanese classical literature Serat Centhini (1814) describes some jamu herbal concoction recipes.
Though possibly influenced by Indian Ayurveda systems, the Indonesia archipelago holds numerous indigenous plants not found in India, including plants similar to those in Australia beyond the Wallace Line. Jamu practices may vary from region to region, and are often not recorded, especially in remote areas of the country. Although primarily herbal, some Jamu materials are acquired from animals, such as honey, royal jelly, milk, and Ayam Kampung eggs.
Herbalists tend to use extracts from parts of plants, such as the roots or leaves, believing that plants are subject to environmental pressures and therefore develop resistance to threats such as radiation, reactive oxygen species and microbial attack to survive, providing defensive phytochemicals of use in herbalism.
Use of plants by animalsEdit
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 chickens, sheep, butterflies, and chimpanzees. The habit of changing diet has been shown to be a physical means of purging intestinal parasites. Sick animals tend to forage plants rich in secondary metabolites, such as tannins and alkaloids.
- "Hard to swallow". Nature. 448 (7150): 105–6. July 2007. Bibcode:2007Natur.448S.105.. doi:10.1038/448106a. PMID 17625521.
- "This Ancient Chinese Remedy Helped Win the Nobel Prize". Time. Retrieved 11 October 2021.
- Su, Xin-zhuan; Miller, Louis H. (November 2015). "The discovery of artemisinin and Nobel Prize in Physiology or Medicine". Science China Life Sciences. 58 (11): 1175–1179. doi:10.1007/s11427-015-4948-7. ISSN 1674-7305. PMC 4966551. PMID 26481135.
- Lack CW, Rousseau J (2016). Critical Thinking, Science, and Pseudoscience: Why We Can't Trust Our Brains. Springer Publishing Company. pp. 212–214. ISBN 9780826194268.
- "Herbal medicine". Cancer Research UK. 2 February 2015. Retrieved 12 November 2018.
- Tyler VE (31 August 1999). "False Tenets of Paraherbalism". Quackwatch. Retrieved 29 October 2016.
- Barrett S (23 November 2013). "The Herbal Minefield". Quackwatch. Retrieved 25 February 2017.
- Nunn J (2002). Ancient Egyptian Medicine. Transactions of the Medical Society of London. Vol. 113. University of Oklahoma Press. pp. 57–68. ISBN 978-0-8061-3504-5. PMID 10326089.
- Atanasov AG, Waltenberger B, Pferschy-Wenzig EM, Linder T, Wawrosch C, Uhrin P, et al. (December 2015). "Discovery and resupply of pharmacologically active plant-derived natural products: A review". Biotechnology Advances. 33 (8): 1582–1614. doi:10.1016/j.biotechadv.2015.08.001. PMC 4748402. PMID 26281720.
- Robson B, Baek OK (2009). The Engines of Hippocrates: From the Dawn of Medicine to Medical and Pharmaceutical Informatics. John Wiley & Sons. p. 50. ISBN 9780470289532.
- Hong F (2004). "History of Medicine in China" (PDF). McGill Journal of Medicine. 8 (1): 7984. Archived from the original (PDF) on 1 December 2013.
- Unschuld P (2003). Huang Di Nei Jing: Nature, Knowledge, Imagery in an Ancient Chinese Medical Text. University of California Press. p. 286. ISBN 978-0-520-92849-7.
- Ackerknecht E (1982). A Short History of Medicine. JHU Press. p. 39. ISBN 978-0-8018-2726-6.
- The Classical Tradition. Harvard University Press. 2010. p. 146. ISBN 978-0-674-03572-0.
- "Traditional medicine". Archived from the original on 27 July 2008.
- Su XZ, Miller LH (November 2015). "The discovery of artemisinin and the Nobel Prize in Physiology or Medicine". Science China Life Sciences. 58 (11): 1175–9. doi:10.1007/s11427-015-4948-7. PMC 4966551. PMID 26481135.
- Baggoley C (2015). "Review of the Australian Government Rebate on Natural Therapies for Private Health Insurance" (PDF). Australian Government – Department of Health. Archived from the original (PDF) on 26 June 2016. Retrieved 12 December 2015.
- "Assessment of clinical safety and efficacy in the preparation of Community herbal monographs for well-established and of Community herbal monographs/entries to the Community list for traditional herbal medicinal products/substances/preparations". European Medicines Agency. 2017. Retrieved 25 February 2017.
- "Herbs at a Glance". National Center for Complementary and Integrative Health, US National Institutes of Health. 21 November 2016. Retrieved 24 February 2017.
- "Clinicaltrials.gov, a registry of studies on herbal medicine". Clinicaltrials.gov, US National Institutes of Health. 2017. Retrieved 25 February 2017.
- Burstein HJ, Gelber S, Guadagnoli E, Weeks JC (June 1999). "Use of alternative medicine by women with early-stage breast cancer". The New England Journal of Medicine. 340 (22): 1733–9. doi:10.1056/NEJM199906033402206. PMID 10352166.
- Egede LE, Ye X, Zheng D, Silverstein MD (February 2002). "The prevalence and pattern of complementary and alternative medicine use in individuals with diabetes". Diabetes Care. 25 (2): 324–9. doi:10.2337/diacare.25.2.324. PMID 11815504.
- Roozbeh J, Hashempur MH, Heydari M (November 2013). "Use of herbal remedies among patients undergoing hemodialysis". Iranian Journal of Kidney Diseases. 7 (6): 492–5. PMID 24241097.
- Bishop FL, Lewith GT (March 2010). "Who Uses CAM? A Narrative Review of Demographic Characteristics and Health Factors Associated with CAM Use". Evidence-Based Complementary and Alternative Medicine. 7 (1): 11–28. doi:10.1093/ecam/nen023. PMC 2816378. PMID 18955327.
- Saad B, Said O (2011). Greco-Arab and Islamic Herbal Medicine: Traditional System, Ethics, Safety, Efficacy, and Regulatory Issues. John Wiley & Sons. p. 80. ISBN 9780470474211.
- Groot Handboek Geneeskrachtige Planten by Geert Verhelst
- Green J (2000). The Herbal Medicine Maker's Handbook: A Home Manual. Chelsea Green Publishing. p. 168. ISBN 9780895949905.
- Romm A (2010). Botanical Medicine for Women's Health. Churchill Livingstone. p. 24. ISBN 978-0-443-07277-2.
- Odinsson E (2010). Northern Lore: A Field Guide to the Northern Mind-Body-Spirit. ISBN 978-1452851433.
- "Aromatherapy". University of Maryland Medical Center. 2017. Archived from the original on 25 October 2017.
- Herz RS (2009). "Aromatherapy facts and fictions: a scientific analysis of olfactory effects on mood, physiology and behavior". The International Journal of Neuroscience. 119 (2): 263–90. doi:10.1080/00207450802333953. PMID 19125379. S2CID 205422999.
- Gilani AH, Shah AJ, Zubair A, Khalid S, Kiani J, Ahmed A, et al. (January 2009). "Chemical composition and mechanisms underlying the spasmolytic and bronchodilatory properties of the essential oil of Nepeta cataria L". Journal of Ethnopharmacology. 121 (3): 405–11. doi:10.1016/j.jep.2008.11.004. PMID 19041706.
- Gaire BP, Subedi L (March 2013). "A review on the pharmacological and toxicological aspects of Datura stramonium L". Journal of Integrative Medicine. 11 (2): 73–9. doi:10.3736/jintegrmed2013016. PMID 23506688.
- Talalay P, Talalay P (March 2001). "The importance of using scientific principles in the development of medicinal agents from plants". Academic Medicine. 76 (3): 238–47. doi:10.1097/00001888-200103000-00010. PMID 11242573.
- Elvin-Lewis M (May 2001). "Should we be concerned about herbal remedies". Journal of Ethnopharmacology. 75 (2–3): 141–64. doi:10.1016/S0378-8741(00)00394-9. PMID 11297844.
- Vickers AJ (2007). "Which botanicals or other unconventional anticancer agents should we take to clinical trial?". Journal of the Society for Integrative Oncology. 5 (3): 125–9. PMC 2590766. PMID 17761132.
- Ernst E (2007). "Herbal medicines: balancing benefits and risks". Dietary Supplements and Health. Novartis Found. Symp. Novartis Foundation Symposia. Vol. 282. pp. 154–67, discussion 167–72, 212–18. doi:10.1002/9780470319444.ch11. ISBN 978-0-470-31944-4. PMID 17913230.
- Newmaster SG, Grguric M, Shanmughanandhan D, Ramalingam S, Ragupathy S (October 2013). "DNA barcoding detects contamination and substitution in North American herbal products". BMC Medicine. 11: 222. doi:10.1186/1741-7015-11-222. PMC 3851815. PMID 24120035.
- Müller JL (1998). "Love potions and the ointment of witches: historical aspects of the nightshade alkaloids". Journal of Toxicology. Clinical Toxicology. 36 (6): 617–27. doi:10.3109/15563659809028060. PMID 9776969.
- Lee MR (December 2006). "Solanaceae III: henbane, hags and Hawley Harvey Crippen". The Journal of the Royal College of Physicians of Edinburgh. 36 (4): 366–73. PMID 17526134.
- Pinn G (November 2001). "Adverse effects associated with herbal medicine". Australian Family Physician. 30 (11): 1070–5. PMID 11759460.
- Lin SH, Yang SS, Chau T, Halperin ML (March 2003). "An unusual cause of hypokalemic paralysis: chronic licorice ingestion". The American Journal of the Medical Sciences. 325 (3): 153–6. doi:10.1097/00000441-200303000-00008. PMID 12640291. S2CID 35033559.
- Lynch CR, Folkers ME, Hutson WR (June 2006). "Fulminant hepatic failure associated with the use of black cohosh: a case report". Liver Transplantation. 12 (6): 989–92. doi:10.1002/lt.20778. PMID 16721764. S2CID 28255622.
- Born D, Barron ML (May–June 2005). "Herb use in pregnancy: what nurses should know". MCN: The American Journal of Maternal/Child Nursing. 30 (3): 201–6, quiz 207–8. doi:10.1097/00005721-200505000-00009. PMID 15867682. S2CID 35882289.
- Boivin J, Schmidt L (July 2009). "Use of complementary and alternative medicines associated with a 30% lower ongoing pregnancy/live birth rate during 12 months of fertility treatment". Human Reproduction. 24 (7): 1626–31. doi:10.1093/humrep/dep077. PMID 19359338.
- Ernst E (February 1998). "Harmless herbs? A review of the recent literature". The American Journal of Medicine. 104 (2): 170–8. doi:10.1016/S0002-9343(97)00397-5. PMID 9528737.
- Izzo AA (2012). "Interactions between herbs and conventional drugs: overview of the clinical data". Medical Principles and Practice. 21 (5): 404–28. doi:10.1159/000334488. PMID 22236736.
- "Herb-Drug Interactions". NCCIH. 10 September 2015. Retrieved 26 June 2019.
- Kuhn MA (April 2002). "Herbal remedies: drug-herb interactions". Critical Care Nurse. 22 (2): 22–8, 30, 32, quiz 34–5. doi:10.4037/ccn2002.22.2.22. PMID 11961942.
- Spolarich AE, Andrews L (Summer 2007). "An examination of the bleeding complications associated with herbal supplements, antiplatelet and anticoagulant medications". Journal of Dental Hygiene. 81 (3): 67. PMID 17908423.
- Nekvindová J, Anzenbacher P (July 2007). "Interactions of food and dietary supplements with drug metabolising cytochrome P450 enzymes". Ceska a Slovenska Farmacie. 56 (4): 165–73. PMID 17969314.
- Cohen R (12 October 2018). "No Wonder It Works So Well: There May Be Viagra In That Herbal Supplement". NPR.org. Retrieved 13 October 2018.
- O'Connor A (3 November 2012). "Herbal Supplements Are Often Not What They Seem". New York Times. Retrieved 12 November 2013.
- Carroll L (24 February 2014). "Herbal medicines: Study raises alarm over labelling". The Sydney Morning Herald, Australia. Retrieved 25 February 2017.
- O'Connor A (3 February 2015). "New York Attorney General Targets Supplements at Major Retailers". The New York Times. Retrieved 3 February 2015.
- Kaplan S (3 February 2015). "GNC, Target, Wal-Mart, Walgreens accused of selling adulterated 'herbals'". The Washington Post. Retrieved 3 February 2015.
- Lin V, McCabe P, Bensoussan A, Myers S, Cohen M, Hill S, Howse G (2009). "The practice and regulatory requirements of naturopathy and western herbal medicine in Australia". Risk Management and Healthcare Policy. 2: 21–33. doi:10.2147/RMHP.S4652. PMC 3270908. PMID 22312205.
- "Becoming a Herbalist". The National Institute of Medical Herbalists. Retrieved 26 June 2019.
- "Legal and Regulatory FAQs". American Herbalist Guild. 24 January 2014. Retrieved 25 November 2020.
- "2017 Warning Letters – Health Fraud". US Food and Drug Administration. 27 February 2017. Retrieved 2 April 2021.
- Porter Jr SE (25 May 2017). "Warning Letter – Herbal Doctor Remedies". U.S. Food and Drug Administration. Retrieved 25 November 2020.
- "Fraudulent Coronavirus Disease 2019 (COVID-19) Products". US Food and Drug Administration. 2 April 2021. Retrieved 2 April 2021.
- Bellamy J (19 November 2020). "FDA and FTC issue more warning letters citing products and services making illegal COVID claims". Science-Based Medicine. Retrieved 2 April 2021.
- "WHO Quality Control Methods for Herbal Materials" (PDF). World Health Organization, Geneva, Switzerland. 2011. Archived from the original (PDF) on 1 August 2014.
- "Herbal medicinal products". European Medicines Agency. 2017. Retrieved 25 February 2017.
- "Botanical Dietary Supplements". Office of Dietary Supplements, US National Institutes of Health. June 2011. Retrieved 25 February 2017.
- "US Dietary Supplement Health and Education Act of 1994". Food and Drug Administration.
- Goldman P (October 2001). "Herbal medicines today and the roots of modern pharmacology". Annals of Internal Medicine. 135 (8 Pt 1): 594–600. doi:10.7326/0003-4819-135-8_Part_1-200110160-00010. PMID 11601931. S2CID 35766876.
- "Licensed Natural Health Products Database: What is it?". Health Canada. 8 December 2016. Retrieved 25 February 2017.
- FDA Issues Regulation Prohibiting Sale of Dietary Supplements Containing Ephedrine Alkaloids and Reiterates Its Advice That Consumers Stop Using These Products Archived 15 September 2007 at the Wayback Machine
- "WHO Traditional Medicine Strategy, 2014–2023" (PDF). World Health Organization. 2013. p. 41. Retrieved 25 February 2017.
- Zhang J, Wider B, Shang H, Li X, Ernst E (2012). "Quality of herbal medicines: challenges and solutions". Complementary Therapies in Medicine. 20 (1–2): 100–6. doi:10.1016/j.ctim.2011.09.004. PMID 22305255.
- Morris CA, Avorn J (September 2003). "Internet marketing of herbal products". JAMA. 290 (11): 1505–9. doi:10.1001/jama.290.11.1505. PMID 13129992.
- Coghlan ML, Haile J, Houston J, Murray DC, White NE, Moolhuijzen P, et al. (2012). "Deep sequencing of plant and animal DNA contained within traditional Chinese medicines reveals legality issues and health safety concerns". PLOS Genetics. 8 (4): e1002657. doi:10.1371/journal.pgen.1002657. PMC 3325194. PMID 22511890.
- Tyler VE, Robbers JE (1999). Tyler's Herbs of Choice: The Therapeutic Use of Phytomedicinals. Routledge. pp. 6–8. ISBN 978-0789001597.
- Tyler VE (31 August 1999). "False Tenets of Paraherbalism". Quackwatch. Retrieved 28 April 2012.
- "Traditional medicine, Factsheet No. 134". World Health Organization. May 2003. Archived from the original on 8 June 2003.
- Moerman DE (1997). "Ethnobotany in North America". In Selin, Helaine (ed.). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Springer. p. 321. ISBN 9780792340669.
- Bussmann RW, Sharon D (November 2006). "Traditional medicinal plant use in Northern Peru: tracking two thousand years of healing culture". Journal of Ethnobiology and Ethnomedicine. 2 (1): 47. doi:10.1186/1746-4269-2-47. PMC 1637095. PMID 17090303.
- Yuan D, Yang X, Guo JC (May 2016). "A great honor and a huge challenge for China: You-you TU getting the Nobel Prize in Physiology or Medicine". Journal of Zhejiang University. Science. B. 17 (5): 405–8. doi:10.1631/jzus.B1600094. PMC 4868832. PMID 27143269.
- Kala CP (2006). "Preserving Ayurvedic herbal formulations by Vaidyas: The traditional healers of the Uttaranchal Himalaya region in India". HerbalGram. 70: 42–50.
- Kala CP (2005). "Health traditions of Buddhist community and role of amchis in trans-Himalayan region of India". Current Science. 89 (8): 1331–38.
- Kala CP (2003). Medicinal plants of Indian trans-Himalaya. Dehradun: Bishen Singh Mahendra Pal Singh. p. 200.
- Petrovska BB (January 2012). "Historical review of medicinal plants' usage". Pharmacognosy Reviews. 6 (11): 1–5. doi:10.4103/0973-7847.95849. PMC 3358962. PMID 22654398.
- Wahono T (21 February 2012). "Jejak Mataram Kuno di Sindoro" [Traces of Ancient Mataram in Sindoro]. KOMPAS (in Indonesian).
- "Jamu dan Lulur, Rahasia Cantik Para Putri Keraton". Tribun Jogja (in Indonesian). 21 May 2013. Retrieved 4 November 2015.
- Society, National Geographic (20 August 2020). "Dividing Species: Wallace Line Map". National Geographic Society. Retrieved 4 May 2022.
- Beers SJ (2001). Jamu: The Ancient Indonesian Art of Herbal Healing. Periplus Editions (HK) Limited. ISBN 978-962-593-503-4.[page needed]
- Vickers A, Zollman C (October 1999). "ABC of complementary medicine: herbal medicine". BMJ. 319 (7216): 1050–3. doi:10.1136/bmj.319.7216.1050. PMC 1116847. PMID 10521203.
- Grassmann J, Hippeli S, Elstner EF (June 2002). "Plant's defence and its benefits for animals and medicine: role of phenolics and terpenoids in avoiding oxygen stress". Plant Physiology and Biochemistry. 40 (6–8): 471–478. doi:10.1016/S0981-9428(02)01395-5.
- Huffman MA (May 2003). "Animal self-medication and ethno-medicine: exploration and exploitation of the medicinal properties of plants". The Proceedings of the Nutrition Society. 62 (2): 371–81. doi:10.1079/pns2003257. PMID 14506884.
- Hutchings MR, Athanasiadou S, Kyriazakis I, Gordon IJ (May 2003). "Can animals use foraging behaviour to combat parasites?". The Proceedings of the Nutrition Society. 62 (2): 361–70. doi:10.1079/pns2003243. PMID 14506883.
- Aronson JK (2008). Meyler's Side Effects of Herbal Medicines. Elsevier. ISBN 9780080932903.
- Braun L, Cohen M (2007). Herbs and Natural Supplements: An Evidence-Based Guide. Elsevier. ISBN 9780729537964.