Vol. 2, #16
April 23, 2005

Q: What is Oregano Oil and what is it used for? - Layperson

A: OREGANO IS A WOODY SHRUB NATIVE to the Mediterranean. The Oregano  Oil (Oil of Oregano) is steam-distilled from fresh or dried leaves. The leaves and flowering tops of more than two dozen fragrant plant species are endowed with a distinctive mildly minty flavor widely recognized as the herb oregano. The most popular of the Origanum species in North America is Origanum vulgare, otherwise known as European oregano or origanum. It's actually a member of the mint family (Labiatae):

Oregano Flowering oregano Scientificclassification Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Lamiales Family: Lamiaceae Genus: Origanum Species: vulgare Binomialname Origanum vulgare

Oregano ( Origanum vulgare ) is a spicy, Mediterranean, perennial herb, particularlycommon in Greek and Italian cuisines. It is the leaves that are used in cooking, andthe dried herb is often more flavourful than the fresh 

The leaves of the oregano plant provide a mild spicy taste that lends itself well to pizza toppings and pasta salads. Aside from its use as a culinary flavoring, the oregano plant also provides a concentrated aromatic oil with distinct healing properties. Texts from ancient times indicate the oil was used as a remedy for seizures and narcotic poisonings, albeit with unknown results.

Health Benefits

The essential oil distilled from oregano contains varying amounts  the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol, compounds that can apparently inhibit the growth of fungi, worms, and possibly other organisms. In fact, some sources even recommend rubbing a drop or two of oregano oil into an area that is itching due to athlete's foot, a common condition caused by the Tinea versicolor fungus.

Mild stomach-settling and cough-clearing qualities are attributed to oregano oil; they are   In the genus Lippia, the same compounds can be found. The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Mild stomach-settling and cough-clearing qualities are attributed to oregano oil; they are likely due to the presence of thymol and carvacrol as well. (Another common culinary herb--thyme--also contains high concentrations of these compounds.) A drop or two of oregano oil mixed with milk or juice may well calm an upset stomach and aid digestion.

Disease-fighting antioxidants have been identified in oregano, although it's not clear whether they appear in the oil as well as in the leaves and other above-ground parts of the plant. Oregano oil has been used as an antiseptic in hand cleansers and shampoos, and as a remedy for headaches when rubbed into the temples.

Specifically, oil of oregano may help to:

  • Alleviate toothaches. Diluted oregano oil rubbed gently into inflamed and aching gums around an ailing tooth may ease pain. The oregano oil may even help to stave off infection given its slight antiseptic properties.

  • Fight Candida overgrowth syndrome. Some nutritionally oriented doctors enlist oregano oil's antifungal actions to fight this syndrome, a condition believed to be caused by an imbalance in the body's fungi and bacteria levels.
  • For toothache: Dilute oregano oil in a small amount of water and dab onto the painful area three or four times a day, as needed for discomfort.

  • For Candida overgrowth syndrome: Place three drops of oregano oil into an empty gelatin capsule or mix the same amount of oil into juice and take three times a day. Several weeks of continuous use may be required for the anti-fungal properties of oil of oregano to clear up a deep-seated Candida infection.

  • Guidelines for Use

  • Try to purchase high-quality oregano oil because the concentration of its active ingredients can vary widely.

  • General Interaction

  • Oil of oregano may reduce the absorption of iron from iron supplements, so take the oregano oil at least two hours before or after consuming iron supplements.

  • Possible Side Effects

  • Side effects are minimal. However, allergic reactions to oregano oil and even a sensitivity to plants in the Labiatae family (thyme, basil, hyssop, marjoram, mint, sage) can occur. Stop taking oregano oil (and any form of oregano) if signs or symptoms of an allergic reaction develop (these may include facial swelling, skin rash, itching, nausea, vomiting, and other symptoms).

  • Cautions

  • Talk to your doctor before taking oregano oil internally if you suffer from iron-deficiency anemia; the oregano might make your condition worse by inhibiting the absorption of iron from foods and supplements.
  • Preliminary research for oregano oil supports its use for infections. Several test-tube studies have shown that oregano oil can inhibit or destroy many strains of bacteria, fungi, and parasites. A handful of human and animal studies, sponsored by an oregano oil manufacturer, have found similar results. Anecdotal evidence supports its use for athlete's foot.

  • Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare (Oregano) growing wild in Tafilalet region.  J Ethnopharmacol. 2004 Jun;92(2-3):251-6.

    The effect of an aqueous extract of Oregano leaves on blood glucose levels was investigated in normal and streptozotocin (STZ) diabetic rats. In normal rats, the blood glucose levels were slightly decreased 6 h after a single oral administration as well as 15 days after once daily repeated oral administration of aqueous Oregano extract (20 mg/kg). After a single dose or 15 daily doses, oral administration of the aqueous extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats. In STZ rats, the blood glucose levels were normalised from the fourth day after daily repeated oral administration of aqueous Oregano extract (20 mg/kg). However, this effect was less pronounced 2 weeks after daily repeated oral administration of oregano extract. In addition, no changes were observed in basal plasma insulin concentrations after treatment in either normal or STZ diabetic rats indicating that the aqueous Oregano extract acted without changing insulin secretion. We conclude that an aqueous extract of Oregano exhibits an anti-hyperglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.

    Immunostimulatory effect of dietary oregano etheric oils on lymphocytes from growth-retarded, low-weight growing-finishing pigs and productivity.  Tijdschr Diergeneeskd. 2004 Mar 15;129(6):178-81.

    The present study was designed to evaluate the possible effect of dietary oregano etheric oils as non-specific immunostimulating agents in growth-retarded, low-weight growing-finishing pigs. Forty-nine growth-retarded (> 10% under average weight in a group) growing-finishing pigs of the same age were assigned to two groups and treated as follows: Group 1 (n = 25): the animals weighed 58 kg and were fed until slaughter ad libitum with a commercial fattening diet supplemented with 3000 ppm commercial oregano feed additive (Oregpig Pecs, Hungary). Oregpig is dried leaf and flower of oregano, enriched with 500 g/kg cold-pressed essential oils of the leaf and flower of oregano. Analysis of Oregpig: 60 g carvacrol and 55 g thymol/kilogram. Group 2 (n = 24): the animals weighed 57.9 kg and were fed until slaughter with the same diet without Oregpig supplementation. Oregano-receiving pigs showed a significantly better average daily gain and feed conversion rate than the non-treated animals (Oregpig group 788.1 +/- 31.3 g, control animals 709 g; 2.96, vs. 3.08, respectively). Mortality was significantly higher in the non-treated animals (oregano group, 1 animal = 4%; control, 8 animals = 33.3%). The proportion of CD4, CD8, MHC class II antigen, and non-T/non-B cells in peripheral blood lymphocytes was significantly higher in the oregano-receiving pigs than in the control animals. The proportion of CD4+ CD8+ double-positive T lymphocytes in peripheral blood and mesenteric lymph nodes was higher in the oregano-receiving pigs than in the control animals. Implication: Dietary oregano improves growth in growth-retarded growing-finishing pigs and has non-specific immunostimulatory effects on porcine immune cells.

    In an abstract in the Journal of the American College of Nutrition that appeared last year, 18 mice were injected with the bacteria Staphylococcus aureus. Three of the six mice that received oregano oil orally survived the infection, while two of the six mice that received the antibiotic vancomycin did. All six of the mice that received no treatment died within three days.

    The same researchers also tested oregano oil's effects on mice who had been injected with the yeast Candida albicans. In the study, published last year in the Journal of Molecular and Cellular Biochemistry, all six of the mice fed oregano oil survived more than 30 days with no sign of Candida infection, while all six mice that were fed just olive oil died within seven days.

    A small study published in Phytotherapy Research in 2000 examined the effects of oregano oil on n adults with the intestinal parasite Blastocystis hominis, which can cause diarrhea, anal itching, and weight loss. Participants took 600 mg of oregano oil daily for six weeks. Eight were completely free of the parasite, and the remaining three participants had a reduction in symptoms.

    How to Take It

    For an infection in your gastrointestinal tract (whether bacterial, fungal, or parasitic), take 0.3 ml of enteric-coated oregano oil capsules three times a day before meals, says Jennifer Brett, N.D., a naturopathic physician and chair of the botanical medicine department at the University of Bridgeport College of Naturopathic Medicine in Connecticut. The enteric coating ensures that the capsule won't release the oil before it reaches your intestines.

    To treat bacterial and fungal infections that occur in other parts of your body, place I drop of the pure oil under your tongue twice a day, suggests Brett.

    For fungal infections on your skin and nails, dilute I teaspoon oregano oil in 2 teaspoons olive oil and apply with a cotton swab to the affected area up to three times a day, she says.

    Oregano oil is potent, so you should not exceed these doses. Also, discontinue use within three weeks, Brett advises.


    Oregano oil is safe for low-dose, short-term use. High doses cause headaches and nausea and may be toxic to the liver. Avoid it if you're pregnant.

    Health Claims

    Oregano oil (Origanum vulgare) contains natural compounds that combat bacterial, fungal, and parasitic infections. It can be used for ailments ranging from athlete's foot to food poisoning.  Contact a healthcare professional familiar with the use of Oregano Oil.

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    DISCLAIMER:  The information in this column, is NOT intended to diagnose and/or treat any health related issues and is provided solely for informational purposes only. Consult the appropriate healthcare professional before making any changes to your healthcare regime. Even what may seem like simple changes in the diet for example, can interact with, and alter, the efficiency of medications and/or the body's response to the medications. Many herbs and supplements exert powerful medicinal effects. Neither the author, nor the website designers, assume any responsibility for the reader's use or misuse of this information.

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