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Read one chapter at a timeCarvacrol and thymol are strong antimicrobials in the laboratory. That isn't proof they cure infections in people.
Dried oregano is stronger than fresh — the opposite of most soft herbs.
It is one of the highest-antioxidant culinary herbs.
Oregano oil is concentrated and can irritate the gut and mouth. Dilute it and don't take it for long stretches.
Oregano grows wild on hot, stony slopes from the Mediterranean across to Iran, and it tastes like where it grows: dry, peppery, a little bitter. Dried oregano is stronger than fresh, which is unusual for a leafy herb. Its oils, carvacrol and thymol, kill bacteria and fungi very effectively in a laboratory dish. That laboratory strength has been oversold online. Eating oregano is good food. Swallowing concentrated oregano oil isn't the same thing, and it isn't harmless.
Known to botanists as Origanum vulgare.
Oregano is a low, bushy perennial of dry hillsides, growing to about half a metre. It has small oval leaves in pairs and clouds of tiny pink-purple flowers in summer. The whole plant is aromatic. Its punch comes from two related compounds, carvacrol and thymol, which are also what make it useful against microbes in the laboratory.
Family: Lamiaceae (mint family).
Oregano is a good test of how you read health claims. The laboratory results are genuinely impressive, and the human evidence is genuinely thin. Holding both of those in mind at once — respecting the plant without believing the internet — is exactly the habit that keeps a person safe with every other herb too.
Older cooking benefits from herbs that add a lot of taste for no salt and no sugar, and oregano is near the top of that list. Its antioxidant content is a bonus rather than the point. The point is that vegetables and beans taste worth eating when they are seasoned well.
Very high in antioxidant compounds.
Warms and settles cold digestion.
Persian temperament: Hot & Dry (3rd degree). Classical Greek and Persian sources both place oregano among the strongly heating, drying herbs, given for damp chests and cold stomachs.
Persian and Greek traditions both call oregano warm and dry. It was used to clear a heavy chest, ease a cough, warm cold digestion, and settle wind. Mountain oregano tea was a common household remedy across Anatolia and the Iranian highlands during cold weather.
It was used: winter cough and heavy chest; cold, sour, or windy digestion.
Traditionally eases a heavy chest and cough.
Wild oregano is gathered on the hills of western Iran, Anatolia, and Greece and dried on rooftops in bundles. It sits at the heart of the za'atar family of blends that stretch from the Levant to the Gulf.
From laboratory work, not from people taking it
Strong antimicrobial (slows the growth of germs) activity in laboratory studies.
Oregano essential oil (the concentrated aromatic oil of the plant) shows consistent antibacterial activity against food-borne organisms in laboratory testing. Rated: moderate evidence.
Carvacrol, the main constituent of oregano oil, has anti-inflammatory effects in animal models. Rated: early research.
Mountain tea is one teaspoon dried oregano in hot water, steeped eight minutes, with honey.
Za'atar-style blend is dried oregano with sumac, toasted sesame and salt.
Gargle is a strong cooled infusion (a drink made by steeping the plant in hot water) used as a throat rinse.
Infused olive oil is dried oregano steeped in warm olive oil for dressing.
Crumble dried oregano between your fingers over hot food to release the oils.
Oregano oil only diluted, only short-term, and preferably with guidance.
Add to tomato dishes, beans, lamb, and roasted vegetables.
Blood thinners — Oregano oil in supplement doses may slow clotting. Cooking amounts of the leaf aren't a concern. (moderate concern)
Diabetes medicine — Concentrated oregano extracts have lowered blood sugar in animal work. Watch readings if you start a supplement. (low concern)
Lithium — Oregano taken as a strong tea has a mild diuretic (makes you pass more urine) effect, which can raise lithium levels. Keep intake steady. (moderate concern)
Concentrated oregano oil can burn the mouth and irritate the stomach. Never take it undiluted.
Do not use oregano oil for long stretches — it disturbs gut bacteria along with everything else.
Laboratory antimicrobial strength isn't evidence it treats an infection in a person.
Avoid medicinal amounts in pregnancy — traditional texts treat strong oregano as a uterine stimulant.
People allergic to mint-family plants (basil, thyme, mint) may react.
Pregnancy and breastfeeding
Oregano as a cooking herb is safe. Oregano oil and concentrated capsules are avoided in pregnancy, as they have been used traditionally to bring on menstruation.
Children
Fine in food from the time a child eats family meals. Oregano oil is far too strong for children and can burn the mouth undiluted.
Older adults
A useful way to make low-salt food taste of something, which matters when blood pressure limits the salt shaker. Check the interaction list if you take warfarin (a blood-thinning medicine) or lithium.
Thyme
The two overlap in chemistry and in use. Together they cover a range of savoury dishes neither manages alone.
Garlic
Oregano and garlic in warm oil is the base of half the cooking around the Mediterranean.
Rosemary
Rosemary is resinous where oregano is peppery. Use a light hand with both or they compete.
Tomato
Dried oregano over cooked tomato is a fixed pairing for good reason: the herb survives long cooking that flattens basil.
Olive oil
Warm the leaf in oil for thirty seconds before it meets anything else. The flavour goes further.
Feta
Salt, fat and a hot dry herb. It needs nothing else on the plate.
Lemon
Lemon juice and oregano make the standard Greek dressing for roast meat and potatoes.
Spring
New growth is soft and mild. Use it fresh and use more of it than a recipe asks for.
Summer
Cut the herb just before it flowers, when the oil in the leaf is at its strongest, and dry it in the shade.
Autumn
Last cuttings go into the jar for winter. Dried oregano is one of the few herbs better dried than fresh.
Winter
The dried leaf carries a whole season of cooking. A pinch rubbed between the palms wakes it up.
Does oregano oil cure infections?
There is no good human trial evidence that it does. Carvacrol kills bacteria and fungi in a dish, which isn't the same as treating an infection in a body. Use oregano as food and see a doctor for infections.
Why is dried stronger than fresh?
Drying concentrates the oils and changes them slightly. Oregano is one of the few herbs where the dried jar beats the fresh bunch for cooking.
End of the Oregano guide