In American Botany|botanical English the term "herb" is also used as an abbreviation of "herbaceous plant". This usage is rarely found in British English.*Herbs have a variety of uses including culinary, medicinal, and in some cases spiritual usage. General usage of the term "herb" differs between culinary herbs and medicinal herbs. In medicinal or spiritual use any of the parts of the plant might be considered "herbs", including leaf|leaves, roots, flowers, seeds, resin, root bark, inner bark (and Vascular cambium|cambium), berry|berries and sometimes the pericarp or other portions of the plant.
The word "herb" is pronounced by many U.S. speakers, or by other U.S. speakers and all other English speakers.*
Culinary herbsCulinary herbs are distinguished from vegetables in that, like spices, they are used in small amounts and provide flavor rather than substance to food.
Many culinary herbs are perennials such as thyme or lavender, while others are Biennial plant|biennials such as parsley or Annual plant|annuals like basil. Some perennial herbs are shrubs (such as rosemary, Rosmarinus officinalis), or trees (such as bay laurel, Laurus nobilis) – this contrasts with Herbaceous plant|botanical herbs, which by definition cannot be woody plants. Some plants are used as both herbs and spices, such as dill weed and dill seed or coriander leaves and seeds. Also, there are some herbs such as those in the mint family that are used for both culinary and medicinal purposes.
Medicinal herbsSome plants contain phytochemicals that have effects on the body. There may be some effects when consumed in the small levels that typify culinary "spicing", and some herbs are toxic in larger quantities. For instance, some types of herbal extract, such as the extract of St. John's-wort (Hypericum perforatum) or of kava (Piper methysticum) can be used for medical purposes to relieve depression and stress. However, large amounts of these herbs may lead to toxic overload that may involve complications, some of a serious nature, and should be used with caution.
Herbs have long been used as the basis of traditional Chinese herbal medicine, with usage dating as far back as the first century Common Era|CE* and far before. In India, the ayurveda medicinal system is based on herbs. Medicinal use of herbs in Western cultures has its roots in the Hippocratic (Greek) elemental healing system, based on a quaternary elemental healing metaphor. Famous herbalist of the Western tradition include Avicenna (Persian), Galen (Roman), Paracelsus (German Swiss), Nicholas Culpeper|Culpepper (English) and the botanically inclined Eclectic physicians of 19th century/early 20th century America (John Milton Scudder, Harvey Wickes Felter, John Uri Lloyd). Modern pharmaceuticals had their origins in crude herbal medicines, and to this day, some drugs are still extracted as fractionate/isolate compounds from raw herbs and then purified to meet pharmaceutical standards.
Some herbs are used not only for culinary and medicinal purposes, but also for psychoactive and/or recreational purposes; one such herb is cannabis.