My diet:

Oregano

No E-numberSpices & herbsOrigin: Plant
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Every diet

VeganYes

It is a dried leaf.

Gluten-freeYes
HalalYes
KosherYes
KetoYes

No carbohydrate.

Low-FODMAPYes
The short answer
Oregano is a dried herb leaf and about as safe as a pantry item gets. It is vegan, gluten-free and keto, and it is worth knowing that the Greek herb and the Mexican one sold under the same name are different plants with different strengths.
Generally safe

Fine for most people at normal amounts.

E-numberNone
Comes fromPlant
What it doesSpices & herbs
Glycemic index—
Daily limitNot set
Also calledOregano, Dried oregano

Rules by country

🇺🇸 US FDANot evaluated as an additive
🇪🇺 European UnionNot evaluated as an additive
🇨🇦 Health CanadaNot evaluated as an additive
CaliforniaNo extra rules

Oregano is an ordinary food ingredient with no E-number, so no regulator treats it as an additive. What applies instead is the general framework for dried herbs and condiments: it has to be declared on the ingredient list, and it is held to the same hygiene and contaminant limits as any other dried leaf crop, including mold and Salmonella.

Daily limit: Experts haven’t set a number because normal food amounts are far below any level of concern.

What is it?

Oregano is the dried leaf of a member of the mint family, and the flavor comes from two volatile oils, carvacrol and thymol, which sit in the little glands on the leaf surface. The more carvacrol, the sharper and more peppery the herb tastes, and the amount varies by plant and by how it was dried, which is why a jar labeled simply oregano can taste flat.

Where it comes from: The dried leaves of Origanum vulgare, a Mediterranean herb used since antiquity and once associated by the ancient Greeks with joy and good luck. It grows wild on dry hillsides across the Mediterranean, and the oil in its leaves carries the herb's character.

Why it’s in food

  • Pizza and Italian cooking
  • Greek and Mediterranean dishes
  • Seasoning blends and rubs
  • Sauces and marinades
  • Stuffing and casseroles

Often found in

PizzaPasta sauceGreek saladLasagnaDried herb blendsRoast chicken stuffingChili con carne

Also listed as: Oregano, Dried oregano, Oregano leaves, Mexican oregano

Health & gut impact

Minerals concentrate as herbs dryBenefit

A dried herb is a concentrated plant: 100 grams of dried oregano is around 265 calories with roughly 9 grams of protein and 34 grams of fibre. A teaspoon is about a gram, so the honest number to look at is the serving on the label rather than the per-100-gram figure.

USDA FoodData Central, oregano

Vitamin K and blood thinnersUnder study

Dried herbs carry a concentrated amount of vitamin K, and oregano is one of the higher ones among the common dried herbs. People on warfarin are told to keep their intake of vitamin K foods steady rather than to avoid them, so a new jar appearing in the weekly shop is worth mentioning to the pharmacist.

NHS, warfarin and other blood-thinning medicines

The oil is not the leafUnder study

Oregano oil sold as a supplement is a very different product from the leaf in the cupboard. It carries a high load of carvacrol and thymol in a small volume, which is why it can irritate skin and, in rare cases, the liver, while a spoonful of dried leaf does not.

FDA, Generally Recognized as Safe (GRAS) determination for oregano oil

What can I use instead?

Thyme

Ratio: Use about twice as much

Best for: A softer, woodier version of the same herb

Marjoram

Ratio: Use the same amount

Best for: A gentler, sweeter relative for soups

Basil

Ratio: Use half the amount

Best for: The sweeter half of an Italian herb pair

Related

More spices & herbs:

BasilBasil is a dried herb leaf: vegan, gluten-free, keto, and one of the safest ingredients in the cupboard. Drying concentrates estragole, a compound EFSA has assessed closely, so a daily spoonful is not the same as a sprig in a sauce.Generally safeBay leafBay leaf is a dried herb that is safe at cooking amounts and fits every diet, including gluten-free and keto. The one thing to know is that the leaf itself is not edible, so pull the whole leaf out before serving the dish.Generally safeBlack pepperBlack pepper is a dried fruit and a genuinely powerful ingredient, because piperine blocks several of the enzymes that metabolize drugs. It is safe in ordinary amounts, and the interaction with medication is the thing worth knowing about.Generally safeCardamomCardamom is a seed pod used as a spice, and at cooking amounts it suits everyone, including gluten-free and keto eaters. Buy green cardamom for baking and chai, and black cardamom for the smoky note of South Asian curries.Generally safe

Common questions

Is Greek oregano different from Mexican oregano?

Yes. The Greek herb, Origanum vulgare, is the one sold in most of Europe and it is milder and sweeter. Mexican oregano is a different plant altogether, with a sharper, more peppery flavor, so a recipe written for one may taste different with the other.

Is dried oregano better than fresh?

Neither is better, they are different. Fresh leaves keep more of the light, floral top note, while dried leaves concentrate the deeper, woody part of the herb and cost far less per spoonful. A pizza is built around dried, and a salad around fresh.

Does oregano go bad?

It loses aroma long before it goes off. Ground and dried oregano fade within months in an open jar, and once the smell has gone the flavor has gone with it. A closed jar in the dark keeps it much longer.

Is oregano safe during pregnancy?

The amounts used in cooking are considered fine, and oregano is one of the herbs most often listed as safe in culinary quantities. Concentrated oregano oil and oregano supplements are a different question and are best avoided without advice.

Is Oregano safe?

Generally safe (95/100). Oregano is an ordinary food ingredient with no E-number, so no regulator treats it as an additive. What applies instead is the general framework for dried herbs and condiments: it has to be declared on the ingredient list, and it is held to the same hygiene and contaminant limits as any other dried leaf crop, including mold and Salmonella.

Is Oregano vegan?

Yes. It is a dried leaf.

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Scientific sources & regulatory citations
  • USDA FoodData Central, oregano
  • NHS, warfarin and other blood-thinning medicines
  • FDA, Generally Recognized as Safe (GRAS) determination for oregano oil