Oregano: Benefits, Uses and Precautions

Dr. Boris Wydoff

Common oregano is an aromatic perennial plant with pink or light purple flowers. According to herbal medicine reference books, oregano herb has traditionally been used for its calming, expectorant, diaphoretic, choleretic, and diuretic effects. It is used to prepare tea, infusions, and decoctions.

What Is This Plant and How Can You Identify It?

Common oregano (*Origanum vulgare L.*) belongs to the mint family, Lamiaceae. It is a perennial herbaceous plant with a creeping rhizome. It usually grows up to 60 cm tall. Some cultivated plants are described as taller, reaching 80–90 cm.

Oregano has upright, four-sided, hairy stems. The upper parts branch extensively and may have a reddish tint. The leaves grow in opposite pairs. They have stalks, an oblong-ovate shape, and finely toothed edges. The upper leaf surfaces are dark green, while the undersides are grayish-green and softly hairy.

One distinguishing feature of oregano is the presence of tiny, translucent black glandular dots on the leaves. Under a magnifying glass, you can see the glands that produce essential oil. These glands are also found on the flower calyx.

The flowers are small and grow in the axils of dark purple bracts. Together, they form a spreading, corymb-like panicle at the top of the stem. The corolla is light purple or pink. The plant is easy to recognize by its strong, pleasant aroma.

According to botanical descriptions, oregano flowers from July through September. It grows in dry and floodplain meadows, open coniferous and birch forests, and among shrubs. The plant is widespread in the European part of Russia, southern Central Asia, and Siberia.

Oregano has several folk names, including motherwort, forest mint, fragrant herb, spiritual flower, and lady's plant. The genus name *Origanum* is associated with the ancient name of the plant, "origan." In Greek, the name is linked to the meaning "ornament of the mountains."

How Can You Distinguish Oregano from Other Plants?

To identify oregano, look beyond its pink-purple flowers and aroma. Botanical descriptions specifically note the structure of its inflorescence: the flowers grow in small groups of two or three in the axils of bracts and form a complex, spreading, corymb-like panicle at the top of the stem. This combination of features helps distinguish oregano from other members of the mint family.

Another identifying feature is the presence of translucent black glandular dots on the undersides of the leaves. They are easy to see under magnification. The leaves are softly hairy, dark green on top, and grayish-green underneath. When harvesting the herb for medicinal use, pay attention to its strong, characteristic smell as well.

Oregano is also cultivated in gardens. Gardening descriptions include plants up to 80–90 cm tall, with branching reddish stems, simple leaves, and purple-pink flowers. Cultivated oregano is propagated from seeds, usually by growing seedlings first.

What Is the Composition of Common Oregano?

According to herbal medicine reference books, oregano herb contains 0.5–1.2% essential oil. Its components include thymol, carvacrol, geranyl acetate, sesquiterpenes, and free alcohols. The herb also contains tannins, with some descriptions reporting levels of up to 20%. Other constituents include bitter compounds, pigments, flavonoids, and ascorbic acid.

The reported vitamin C content is approximately 565 mg% in oregano leaves, 170 mg% in the flowers, and 60 mg% in the stems. The seeds contain a fixed oil, which may account for up to 28% of their composition.

Oregano herb also accumulates magnesium, zinc, selenium, and other trace elements. Essential oil content can vary depending on the plant's growth and development.

Why Does Essential Oil Content Vary?

Oregano is an essential-oil-producing plant. Reference books note that the amount of essential oil in medicinal plants depends on the biological characteristics of the species and climatic conditions. As a result, the composition of herbs collected in different places and at different times may vary.

Oregano is particularly known for containing thymol and carvacrol. Its essential oil also contains geranyl acetate, sesquiterpenes, and free alcohols. The plant's aroma comes from these volatile compounds.

Interestingly, essential oils also play a role in the plant's survival. Botanical descriptions classify oregano among steppe plants that release substantial amounts of essential oils. As these substances evaporate, they help the plant conserve water in hot conditions.

Common Oregano: Benefits and Traditional Uses

According to herbal medicine reference books, preparations made from oregano herb are described as having calming, pain-relieving, antiseptic, expectorant, diuretic, diaphoretic, and choleretic effects. Reference books also describe effects on digestive and bronchial gland secretions, intestinal peristalsis, and intestinal tone.

Oregano has traditionally been used to support digestion. Folk accounts describe its use for poor appetite, flatulence, and reduced intestinal tone. These accounts relate to the plant's traditional use.

Oregano is among the herbs traditionally used in calming teas. Herbal medicine books describe its use for insomnia, nervous disorders, headaches, and low mood.

In folk practice, oregano was used for seasonal cold symptoms. Strong oregano tea was taken to promote sweating. The herb's expectorant properties are also described in herbal medicine reference books.

Historical herbal books mention combining oregano with honey. These accounts describe traditional ways of using the plant. They do not replace medical care for illnesses.

According to reference books, oregano was included in aromatic herbal mixtures for warm and cold poultices, baths, medicinal teas intended to promote sweating or relieve gas, and gargles.

Folk medicine also describes external use. A water-based oregano decoction was taken orally and used to wash areas affected by eczema. This is a traditionally documented use.

What Conditions Was Oregano Traditionally Used For?

Oregano was widely used in historical herbal medicine. One historical source called it a "woman's herb" and described the use of decoctions and infusions for various women's complaints, including menstrual pain and irregular cycles. There are also accounts of its use during menopause.

Folk accounts associate oregano with use for migraines, insomnia, loss of appetite, gastritis, hemorrhoids, and intestinal atony. Traditionally, people also sniffed powder made from dried leaves for headaches and runny noses.

These accounts reflect the history of folk herbal medicine and do not establish proven effectiveness for the conditions listed. It is especially important not to apply historical treatment recommendations to pregnancy, breastfeeding, or chronic illnesses without consulting a qualified healthcare professional.

How Can You Use Common Oregano?

Oregano is used as an aromatic herb. Its leaves and flowers have traditionally been used as a tea substitute. Dried oregano is also used as a seasoning. According to reference books, oregano was added when preparing kvass and wort, as well as when pickling cucumbers and cabbage. The plant has also been used in the perfume industry.

Oregano is a good source of nectar for honeybees. It has also been used for household purposes. A strong decoction of the flowers can dye wool orange. The herb has also been used to protect fur and woolen garments from moths.

How Was Oregano Used Around the Home?

Oregano has been known in Russia for a long time. Ethnographic accounts describe how bundles of dried herb were traditionally hung in peasant homes. People associated the plant with protective properties and valued its fragrance indoors.

Oregano was believed to repel flies, mosquitoes, and moths. The plant was used for more than its scent: a strong decoction of its flowers was used to dye wool orange. Beekeepers also valued it as a good nectar source. Traditional household accounts additionally mention using oregano to treat beehives against ants.

How to Brew Common Oregano and Make Tea

Herbal medicine books describe using oregano as tea, an infusion, or a decoction. The preparation method depends on the intended use. Historical accounts mention drinking an infusion or decoction prepared in the manner of tea.

One calming herbal tea blend consists of equal parts mint, lemon balm, thyme, oregano, and German chamomile. This is a traditional herbal mixture.

A tonic tea containing St. John's wort is also described: St. John's wort — 1 part, thyme — 2 parts, oregano — 4 parts, and mint — 1 part. When using blends containing several herbs, consider the properties of each ingredient. St. John's wort has important precautions, so these blends should not be used without taking individual circumstances into account.

Oregano alone has traditionally been brewed as tea. Historical accounts mention drinking this tea during fieldwork. Within traditional herbal medicine, the benefits of oregano tea are associated mainly with the herb's described calming and sweat-promoting properties. However, traditional use does not establish that the drink can treat specific diseases.

How to Harvest and Store the Herb

Oregano herb is harvested for medicinal use. According to medicinal plant harvesting reference books, the flowering tops, 20–30 cm long, are cut with knives or sickles.

When harvesting, it is recommended to leave some plants for natural seed propagation: 1–2 plants per 10 m² of land.

After harvesting, the plant material is dried promptly in attics or under shelters. Drying continues until the stems become brittle. The herb is then threshed, and the coarse stems are removed.

Good-quality oregano should retain its natural color, have a pleasant aromatic smell, and taste bitter-spicy with a slightly astringent note.

One reference book specifies the following quality requirements for the harvested material: moisture content up to 13%, blackened or browned plant parts no more than 7%, plants with stems no more than 40%, and organic and mineral impurities no more than 1% each.

Why Is It Important Not to Overharvest Oregano?

Oregano is widespread, but that does not mean its patches can be cut down completely without limits. Botanical and local-history descriptions note that excessive or careless harvesting has led to noticeable declines in the numbers and distribution of medicinal plants in some regions. Common oregano is among the species mentioned.

For this reason, some plants should be left to produce seeds. This approach is particularly important in areas where oregano grows in small groups rather than forming large patches.

Historically, harvesting medicinal plants was also part of local trade. Oregano and other wild plants were collected in villages and delivered to pharmacies or sold to plant buyers. Before the Russian Revolution, medicinal plant materials were also purchased by representatives of foreign companies.

How to Find Common Oregano Abroad

In other countries, this plant may have different names, so when buying it, check the Latin name *Origanum vulgare* as well as the local name.

• United States: oregano.
• Germany: Oregano, Echter/Gemeiner Dost, Wilder Majoran.
• France: origan, origan commun, marjolaine sauvage.
• Latin name: *Origanum vulgare*. The word "marjoram" on its own may refer to a different plant species.

Oregano is sold as loose dried herb, tea bags, liquid extracts or tinctures, and capsules. Look for leaves and/or flowering aerial parts rather than roots or fruits. Check capsules and extracts particularly carefully, as some contain oregano oil or other added ingredients.

In the United States, look in health food stores, herbal shops, tea shops, and online. In Germany, try pharmacies (Apotheken), health food stores (Reformhäuser), tea shops, and online retailers. In France, look in pharmacies, herbalist shops (herboristeries), organic food stores, and online.

Check the package for the name *Origanum vulgare*, the plant part used, and whether the product is a food-grade herbal tea or a medicinal product. For an organic product, look for genuine certification rather than relying on the word "natural" alone.

Sales regulations differ by country. For example, in the United States, dietary supplements do not undergo FDA premarket approval for safety or effectiveness. In Germany, if you want medicinal herbal tea, specifically ask a pharmacist for Arzneitee.

Common Oregano: Contraindications and Possible Side Effects

Oregano is used as a food in culinary amounts. However, concentrated forms require caution. If you have previously had an allergic reaction to oregano, stop using it. Cross-sensitivity with other plants in the mint family is possible.

Medicinal doses of oregano require caution during pregnancy. The NIH LiverTox resource warns that doses comparable to those found in dietary supplements may have abortifacient effects. The safety of medicinal doses during pregnancy has not been adequately studied.

There is insufficient information about the safety of medicinal doses during breastfeeding. Oregano should be used cautiously in these amounts. A safe medicinal dose for children has not been established. Adult doses should not automatically be used for children.

Taking large amounts orally may cause abdominal discomfort, heartburn, changes in bowel function, nausea, vomiting, dizziness, or headaches. Applying oregano to the skin may cause allergic contact dermatitis. Severe allergic reactions, including anaphylaxis, have rarely been reported.

Oregano essential oil should not be treated like an ordinary culinary seasoning. Concentrated forms are different from using the plant as food.

When to See a Doctor

If you develop signs of an allergic reaction, severe nausea, vomiting, dizziness, or other unusual symptoms after using oregano, seek medical attention. During pregnancy and breastfeeding, discuss medicinal use of the herb with your doctor beforehand. If you take medication, have a chronic condition, or want to use oregano in medicinal doses, seek personalized advice from a doctor or pharmacist.

Do not give children medicinal forms of oregano without advice from a qualified healthcare professional.

Boris Wydoff — naturopath and author, Ph.D. in nutrition. For over fifty years I have helped people restore health through nutrition, cleansing and the power of the mind — in Europe, America and Asia. About the author →

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