Oregano (US pron.: // or UK //), scientifically named Origanum vulgare by Carolus Linnaeus, is a common species of Origanum, a genus of the mint family (Lamiaceae). It is native to warm-temperate western and southwestern Eurasia and the Mediterranean region.
Oregano is a perennial herb, growing from 20–80 cm tall, with opposite leaves 1–4 cm long. Oregano will grow in a pH range between 6.0 (mildly acid) and 9.0 (strongly alkaline) with a preferred range between 6.0 and 8.0. The flowers are purple, 3–4 mm long, produced in erect spikes. It is sometimes called wild marjoram, and its close relative O. majorana is known as sweet marjoram.
Description and biology 
Oregano is related to the herb marjoram, oregano also being known as wild marjoram. It is a perennial, although it is grown as an annual in colder climates, as it often does not survive the winter months. It grows to 20 inches, with purple flowers and spade-shaped, olive-green leaves. It prefers a hot, relatively dry climate, but will do well in other environments. To cultivate, it should be planted in early spring, in fairly dry soil, with full sun. The plants should be spaced 12 inches apart.
Many subspecies and strains of oregano have been developed by humans over centuries for their unique flavors or other characteristics. Tastes range from spicy or astringent to more complicated and sweet. Simple oregano sold in garden stores as Origanum vulgare may have a bland taste and larger, less dense leaves, and is not considered the best for culinary uses, with a taste less remarkable and pungent. It can pollinate other more sophisticated strains, but the offspring are rarely better in quality.
The related species, Origanum onites (Greece, Turkey) and O. syriacum (West Asia), have similar flavors. A closely related plant is marjoram from Turkey, which, however, differs significantly in taste, because phenolic compounds are missing from its essential oil. Some varieties show a flavor intermediate between oregano and marjoram.
Notable subspecies are:
- Origanum vulgare gracile (= O. tyttanthum) is originally from Kyrgyzstan, and has glossy green leaves and pink flowers. It grows well in pots or containers, and is more often grown for added ornamental value than other oregano. The flavor is pungent and spicy.
- Origanum vulgare hirtum (Italian oregano, Greek oregano) is a common source of cultivars with a different aroma from those of O. v. gracile. Growth is vigorous and very hardy, with darker green, slightly hairy foliage. Generally, it is considered the best all-purpose culinary subspecies.
Example cultivars are:
- Aureum – Golden foliage (greener if grown in shade), mild taste. It has gained the Royal Horticultural Society's Award of Garden Merit.
- Greek Kaliteri – O. v. hirtum strains/landraces, small, hardy, dark, compact, thick, silvery-haired leaves, usually with purple undersides, excellent reputation for flavor and pungency, as well as medicinal uses, strong, archetypal oregano flavor (Greek kaliteri: the best).
- Hot & Spicy – O. v. hirtum strain
- Nana – dwarf cultivar
Cultivars traded as Italian, Sicilian, etc. are usually hardy sweet marjoram (O. ×majoricum), a hybrid between the southern Adriatic O. v. hirtum and sweet majoram (O. majorana). They have a reputation for sweet and spicy tones, with little bitterness, and are prized for their flavor and compatibility with various recipes and sauces.
Oregano is an important culinary herb, used for the flavor of its leaves, which can be more flavourful when dried than fresh. It has an aromatic, warm and slightly bitter taste, which can vary in intensity. Good quality oregano may be strong enough almost to numb the tongue, but the cultivars adapted to colder climates often have a lesser flavor. Factors such as climate, seasons and soil composition may affect the aromatic oils present, and this effect may be greater than the differences between the various species of plants. Among the chemical compounds contributing to the flavour are carvacrol, thymol, limonene, pinene, ocimene, and caryophyllene.
Oregano's most prominent modern use is as the staple herb of Italian-American cuisine. Its popularity in the US began when soldiers returning from World War II brought back with them a taste for the “pizza herb”, which had probably been eaten in southern Italy for centuries. There, it is most frequently used with roasted, fried or grilled vegetables, meat and fish. Unlike most Italian herbs, oregano combines well with spicy foods, which are popular in southern Italy. It is less commonly used in the north of the country, as marjoram generally is preferred.
In Turkish cuisine, oregano is mostly used for flavoring meat, especially for mutton and lamb. In barbecue and kebab restaurants, it can be usually found on table, together with paprika, salt and pepper.
The dried and ground leaves are most often used in Greece to add flavor to Greek salad, and is usually added to the lemon-olive oil sauce that accompanies many fish or meat barbecues and some casseroles.
Oregano is also used by chefs in the southern Philippines to eliminate the odor of carabao or water buffalo when boiling it, while simultaneously imparting flavor.
|This section requires expansion with: Additional medicinal uses with WP:MEDRS citations. (November 2010)|
Oregano is high in antioxidant activity, due to a high content of phenolic acids and flavonoids. In test-tube studies, it also has shown antimicrobial activity against strains of the food-borne pathogen Listeria monocytogenes. These in vitro findings have not translated to in vivo results, and it has not been shown to be of any benefit in humans for any medical condition.
In 2005, the US Federal Trade Commission brought legal action against a firm that had claimed oil of oregano treated colds and flus, and that oil of oregano taken orally treated and relieved bacterial and viral infections and their symptoms, saying the representations were false or were not substantiated at the time the representations were made, and that they were therefore a deceptive practice and false advertisements. The final stipulation on the matter said no representation as to any health benefit could be made without "…competent and reliable scientific evidence…".
Other plants called "oregano" 
- Cuban oregano (Plectranthus amboinicus, formerly Coleus aromaticus), also of the mint family (Lamiaceae). Sometimes also called "Mexican mint or Mexican thyme", it has large and somewhat succulent leaves.
- Mexican oregano (Lippia graveolens) is not of the mint, but of the closely related vervain family (Verbenaceae), including, e.g., the lemon verbena (Aloysia citrodora). It is a highly studied herb that is said to be of some medical use and is common in curandera (female shamanic practices) in Mexico and the Southwestern United States. The flavor of Mexican oregano is somewhat more like savory, instead of the piney hint of rosemary flavor in oregano. It is becoming more commonly sold outside of Mexico, especially in the United States. It is sometimes used as a substitute for epazote leaves; this substitution would not work the other way round.
- Poliomintha longiflora is also occasionally called orégano in Friday America.
Oregano is the anglicised form of the Italian word origano, or possibly of the medieval Latin organum; this latter is used in at least one Old English work. Both were drawn from the Classical Latin term origanum, which probably referred specifically to sweet marjoram, and was itself a derivation from the Greek ὀρίγανον (origanon), which simply referred to "an acrid herb". The etymology of the Greek term is often given as oros ὄρος "mountain" + the verb ganousthai γανοῦσθαι "delight in", but the Oxford English Dictionary notes it is quite likely a loanword from an unknown North African language.
See also 
- "Origanum vulgare L. oregano". Plants Database, United States Department of Agriculture, http://plants.usda.gov/. Retrieved 30 January 2011.
- "Growing Culinary Herbs In Ontario". Ontario Ministry of Agriculture, Food & Rural Affairs, http://www.omafra.gov.on.ca. Retrieved 30 January 2011.
- Peter, K. V. (2004). "14.3.1 Growth habit of wild oregano populations". Handbook of herbs and spices. Volume 2. Abington Hall, Abington: Woodhead Publishing Limited. p. 219. ISBN 1-85573-721-3. Retrieved 30 January 2011.
- "Herbs". Government of Saskatchewan, http://www.agriculture.gov.sk.ca. September 2009. Retrieved 30 January 2011.
- Organic Gardening
- http://gernot-katzers-spice-pages.com/engl/Orig_vul.html. Oregano leaves are more flavorful when dried
- Epikouria Magazine, Fall/Spring 2007
- Faleiro, Leonor; et al. (2005). "Antibacterial and Antioxidant Activities of Essential Oils Isolated from Thymbra capitata L. (Cav.) and Origanum vulgare L". J. Agric. Food Chem. 53 (21): 8162–8168. doi:10.1021/jf0510079. PMID 16218659.
- Dragland, Steinar; et al. (1 May 2003). "Several culinary and medicinal herbs are important sources of dietary antioxidants". J Nutr. 133 (5): 1286–1290. PMID 12730411.
- Barrett, Stephen (13 June 2005). "Regulatory Actions against Michael Teplitsky, M.D.". Quackwatch. Retrieved 2 November 2010.
- "Complaint for permanent injunction and other equitable relief" (PDF). FEDERAL TRADE COMMISSION. Plaintiff, v GREAT AMERICAN PRODUCTS, INC., PHYSICIAN'S CHOICE, INC., STEPHAN KARIAN, and MICHAEL TEPLITSKY, M.D., a/k/a MICHAEL TEPLISKY, M.D., Defendants; United States District Court, Northern District of Florida, Civil Action No. 3:05-CV-00170-RV-MD. United States Federal Trade Commission. 10 May 2005. pp. 32–33. Retrieved 2 November 2010.
- "Stipulated final order for permanent injunction and settlement of claims for monetary relief" (PDF). FEDERAL TRADE COMMISSION. Plaintiff, v GREAT AMERICAN PRODUCTS, INC., PHYSICIAN'S CHOICE, INC., STEPHAN KARIAN, and MICHAEL TEPLITSKY, M.D., a/k/a MICHAEL TEPLISKY, M.D., Defendants; United States District Court, Northern District of Florida, Civil Action No. 3:05-CV-00170-RV-MD. United States Federal Trade Commission. 20 May 2005. p. 10. Retrieved 2 November 2010.
- ὀρίγανον, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
- origanum, on Oxford Dictionaries
- Oxford English Dictionary Online. Draft revision for "oregano", June 2008; draft revision for "origanum", March 2009; draft revision for "organum", June 2008
|Wikimedia Commons has media related to: Origanum vulgare|
- How to Grow Oregano Information about planting, propagating and growing oregano.
- Flora Europaea: Origanum vulgare
- Germplasm Resources Information Network: Origanum vulgare
- Gernot Katzer's Spice Pages: Oregano (Origanum vulgare L.)
- Inhibition of enteric parasites by emulsified oil of oregano
- Oregano Herb Profile: vulgare