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Photo copyright Martin Wall

Oregano/Wild Marjoram

Botanical name: Origanum vulgare

Parts used and where grown: Oregano is an aromatic perennial herb that can grow to about two feet in height. It is native to Europe and Asia but is cultivated worldwide. In addition to European oregano, there are several types of related species, including Greek/Turkish (Origanum onites) oregano and Mexican (Lippia graveolens, Lippa palmeri) oregano. The leaves and dried herb as well as the volatile oil are used medicinally.1



Oregano has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating Health Concerns
1Star Chronic candidiasis
Indigestion
Infection
Yeast infection
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies): The name Oreganum is the contraction of two Greek words, oros meaning mountain and ganos meaning joy. Together the words suggest the beauty that oregano lends to the fields and hilltops on which it grows.2 Oregano was used extensively by the Greeks for conditions ranging from convulsions to heart failure. Nineteenth-century American Eclectic physicians (doctors who recommended herbal medicines) employed oregano as both a general tonic and to promote menstruation.3

Active constituents: This dried herb contains several constituents, including volatile oil (up to 3%), such as carvacrol, thymol, and borneol, plus flavonoids, rosmarinic acid, triterpenoids (e.g. ursolic and oleanolic acid), sterols, and vitamin A and vitamin C.4 The thymol and carvacrol contents in oregano are responsible for its antimicrobial and antifungal effects.5 A test tube study demonstrated that oil of oregano, and carvacrol in particular, inhibited the growth of Candida albicans far more effectively than a commonly employed antifungal agent called calcium magnesium caprylate.6 Clinical studies are still needed to confirm these actions in humans.

In addition to its anti-fungal action, and according to the results of another test tube study from Australia, oregano oil has a strong anti-microbial action against a wide number of bacteria, including Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, and Staphylococcus aureus.7 Other test tube studies have shown that oregano from the Mexican (Lippia) species was more effective than the prescription medication tinidazol in inhibiting the parasite giardia (Giardia duodenalis).8 In another test tube study, volatile oils of oregano, thyme, cinnamon, and cumin were individually able to stop the growth of another food-borne pathogen called Aspergillus parasiticus. Higher concentrations of these volatile oils were also able to stop the production of a potent poison from Aspergillus called aflatoxin.9 Together these facts suggest the volatile oils found in oregano have an important role in preventing the spoilage of food and in reducing the risk of ingesting harmful bacteria, fungi, and parasites. Again, these actions have not yet been confirmed by human clinical trials.

The German Commission E does not approve oregano for any medical indication.10

How much is usually taken? Oregano can be made into a tea by steeping 1 to 2 teaspoons (5–10 grams) of the dried herb in hot water for ten minutes. This tea can be consumed three times a day.11 The amount of oregano oil required for internal or topical anti-fungal activity is currently unknown.

Are there any side effects or interactions? Oregano should not be used during pregnancy as it stimulates menstruation and may cause miscarriage.12 The oil should not be used internally by anyone. Topically, the volatile oil of oregano may be moderately irritating to skin and can be a potent mucous membrane irritant. It should not be applied topically to mucous membranes in greater than a 1% concentration.13 Children less than two years of age and people with damaged or very sensitive skin should not use the oil topically.14

At the time of writing, there were no well-known drug interactions with Oregano/Wild Marjoram.

References:

1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients, 2nd ed. New York: John Wiley & Sons, 1996, 398–9.

2. Grieve M. A Modern Herbal, vol II. New York: Dover Publications, 1982, 520–1.

3. Castleman M. The Healing Herbs. Emmaus, PA: Rodale Press, 1991, 275–6.

4. Wren RC. Potter’s New Cyclopedia of Botanical Drugs and Preparations. Essex, England: C.W. Daniel, 1985, 185.

5. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients, 2nd ed. New York: John Wiley & Sons, 1996, 398–9.

6. Stiles JC, Sparks W, Ronzio RA. The inhibition of Candida albicans by oregano. J Applied Nutr 1995;47:96–102.

7. Hammer KA, Carson CF, Riley TV. Antimicrobial activity of essential oils and other plant extracts. J Appl Microbiol 1999;86:985–90.

8. Ponce MM, Navarro AI, Martinez GMN, et al. In vitro effect against Giardia of 14 plant extracts. Rev Invest Clin 1994;46:343–7 [in Spanish].

9. Tantaoui EA, Beraoud L. Inhibition of growth and aflatoxin production in Aspergillus parasiticus by essential oils of selected plant materials. J Environ Pathol Toxicol Oncol 1994;13:67–72.

10. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 358–9.

11. Peirce A. Practical Guide to Natural Medicines. New York: William Morrow and Co., 1999, 476–7.

12. Brinker F. Herb Contraindications and Drug Interactions 2nd ed. Sandy, OR: Eclectic Medical Publishers, 1998, 181.

13. Tisserand R, Balacs T. Essential Oil Safety. New York: Churchill Livingston, 1996, 156–7.

14. Tisserand R, Balacs T. Essential Oil Safety. New York: Churchill Livingston, 1996, 156–7.