Oregano vs. Parsley: A Hearty Dried Herb and a Delicate Fresh One

Oregano and parsley come from different plant families and do different jobs. Oregano is a mint-family herb whose oil is built on the phenols carvacrol and thymol, and it holds up to drying and long cooking.¹²³ Parsley is a carrot-family herb with a mild, slightly bitter flavor and very little essential oil, and it is at its best fresh and added late.⁴⁵⁶⁷ They are often suggested as stand-ins for each other, but only one direction comes close, and only for color or a green note, not for flavor.

Side by side

The flavor row is our description. Britannica describes Greek and Italian culinary oreganos as having a strong aroma and a warm, pungent taste,¹ and calls parsley mildly aromatic.⁴ PROSEA describes parsley oil’s flavor as warm but slightly burning and bitter.⁵

The chemistry, sample by sample

These are essential-oil figures from particular samples, collected in two reference works. They come from different studies and should not be merged.

The two herbs share no lead compound, and parsley carries far less oil to begin with. That is the chemistry behind the everyday experience that oregano flavors a dish while parsley freshens it.

The differences that change a dish

Dried or fresh

Oregano is one of the herbs America’s Test Kitchen’s Danielle Lapierre says dry well; parsley is on her list of herbs better fresh, which she says are much weaker in flavor once dried.⁶ In ATK’s dried-versus-fresh tests, dried oregano held up reasonably well in dishes with more than 20 minutes of cooking and plenty of liquid.³

A common explanation says oregano is used dried because fresh oregano is too strong, and that drying makes it milder. The University of Delaware’s extension guide gives the general rule the other way: dried herbs are stronger than fresh.¹⁵ Oregano dries well because its flavor survives the process, not because drying tames it.

When it goes in

LSU AgCenter groups parsley with the delicate herbs added a minute or two before cooking ends, and oregano with the less delicate herbs.⁷ In a tomato sauce, oregano can go in early and parsley at the end.

Flat-leaf and curly parsley

PROSEA says flat-leaved parsley is stronger flavored than the curly type and that curly leaves are commonly used for garnishing and seasoning.⁵ America’s Test Kitchen recommends flat-leaf when parsley is a major player in a recipe, as in its tabbouleh and salsa verde.¹² See Italian parsley vs. curly parsley.

Where each one belongs

Britannica calls oregano essential in Italian pizza and pasta sauces, Greek salads and gyros, and says it became widely known in the United States after World War II, when returning soldiers who had developed a taste for Italian food made it popular.¹ Parsley is one of the fines herbes, with chives, tarragon and chervil.¹⁶ By common practice it is also the base of chimichurri, persillade and gremolata; we did not find a source we could open that documents those recipes.

Can one stand in for the other?

Only in a limited way, and neither copies the other’s flavor.

• Oregano in place of parsley (Method). Healthline says to use less oregano than parsley, because oregano’s flavor is much stronger.¹⁷ No published ratio was found. Start with about a quarter of the parsley amount and taste, and keep oregano out of dishes where parsley is the main ingredient, such as tabbouleh or a parsley sauce (editorial). Our parsley substitutes page uses the same starting point.
• Parsley in place of oregano (Method). The Spice House suggests parsley among the swaps for Greek or Mediterranean oregano,¹⁸ and A Couple Cooks says a small handful of flat-leaf parsley could work in a pinch.¹⁹ Neither gives an amount. Parsley adds a green note, not oregano’s warmth. Use it fresh, near the end, starting with the same amount as the oregano. See oregano substitutes for closer matches such as marjoram.
• Color only. Dried parsley flakes look much like dried oregano in a soup or meatball mix and add little flavor (editorial).

What isn’t known

• No published measurement compares the flavor strength of oregano and parsley; the starting amounts are Method.
• We found no source for the claim that oregano and parsley are among the most popular herbs in American cooking, or that pizza sauce is known for an especially strong oregano flavor.
• Persillade, chimichurri and parsley with hummus are widely described, but we could not open a source documenting them.

Related

• Profiles: oregano, parsley, marjoram, chervil
• Substitutes: oregano substitutes, parsley substitutes
• Comparisons: basil vs. parsley, cilantro vs. parsley, chervil vs. parsley, oregano vs. thyme, basil vs. oregano, cilantro vs. oregano
• Fresh and dried: fresh oregano vs. dried, fresh parsley vs. dried
• Too much oregano? and too much parsley?