Herbal Medicine or 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, medical herbalism, herbal medicine, herbology, and phytotherapy.
The scope of herbal medicine is sometimes extended to include fungal and bee products, as well as minerals, shells and certain animal parts.
Unlike many forms of alternative medicine, herbalism is widely considered by the medical community to have a scientific basis and even plays an important role in the formulation of many medications and dietary supplements, such as oripavine and vitamin C supplements.
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, substances such as alkaloids serve as plant defence mechanisms against predation by microorganisms, insects, and herbivores.
Many of the herbs and spices used by humans to season food yield useful medicinal compounds. Similar to prescription drugs, a number of herbs are thought to be likely to 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.”
Herbalists are often trained to take well-established risks into consideration when patients consult them.
Anthropology Of Herbalism
Further information: Zoopharmacognosy People on all continents have used hundreds to thousands of indigenous plants for treatment of ailments since prehistoric times.
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.
These herbs appear to have been used to treat the parasites found in his intestines. Anthropology or anthropologists theorize that animals evolved a tendency to seek out bitter plant parts in response to illness.
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.
Researchers from Ohio Wesleyan University found that some birds select nesting material rich in antimicrobial agents which protect their young from harmful bacteria. Sick animals tend to forage plants rich in secondary metabolites, such as tannins and alkaloids.
Since these phytochemicals often have antiviral, antibacterial, antifungal and anthelmintic 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.
The use of herbs and spices in cuisine developed in part as a response to the threat of food-borne pathogens.
Studies show that in tropical climates where pathogens are the most abundant, recipes are the most highly spiced. Further, the spices with the most potent antimicrobial activity tend to be selected.
In all cultures vegetables are spiced less than meat, presumably because they are more resistant to spoilage.
Herbs In History
Borage from Project Gutenberg EBook of Culinary Herbs: Their Cultivation Harvesting Curing and Uses, by M. G. Kains In the written record, the study of herbs dates back over
5,000 years he Sumerians, who described well-established medicinal uses for such plants as laurel, caraway, and thyme.
Ancient Egyptian medicine 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.
Indian Ayurveda medicine has used herbs such as turmeric possibly as early as 1900 B.C.
Many other herbs and minerals used in Ayurveda were later described by ancient Indian herbalists such as Charaka and Sushruta during the 1st millenium BC.
The Sushruta Samhita attributed to Sushruta in the 6th century BC describes 700 medicinal plants, 64 preparations from mineral sources, and 57 preparations based on animal sources.
The first Chinese herbal book, the Shennong Bencao Jing, compiled during the Han Dynasty but dating back to a much earlier date, possibly 2700 B.C., lists 365 medicinal plants and their uses – including ma-Huang, the shrub that introduced the drug ephedrine to modern medicine.
Succeeding generations augmented on the Shennong Bencao Jing, as in the Yaoxing Lun (Treatise on the Nature of Medicinal Herbs), a 7th century Tang Dynasty treatise on herbal medicine.
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 pattern 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 hand, recommended large doses of 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 than 500 plants that remained an authoritative reference into the 17th 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.
A number of herbs are thought to be likely to 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 they can be recommended for 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 patient.
Herbal remedies can also be dangerously contaminated, and herbal medicines without established efficacy, may unknowingly be used to replace medicines that do have corroborated efficacy.
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 defence 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 colourful 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 liquorice ingestion and consequently professional herbalists avoid the use of liquorice where they recognise 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 where a high degree of confidence of a risk long term adverse effects can be asserted include ginseng, which is unpopular among herbalists for this reason, 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 patient should inform a herbalist of their consumption of orthodox 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.