Mexican Oregano vs. Oregano: Two Plant Families, One Shared Flavor

Mexican oregano and oregano come from different plant families. Mexican oregano is the leaf of Lippia graveolens, a shrub in the verbena family (Verbenaceae); oregano is Origanum vulgare, a perennial in the mint family (Lamiaceae).¹²³ They still taste alike because both oils are built on the same two phenols, thymol and carvacrol, in different proportions.⁴⁵ In America’s Test Kitchen’s side-by-side tasting the differences in finished dishes were minimal, with the Mexican type the stronger of the two.⁶

Side by side

The flavor row is our description, and it fits what the sources report. PROSEA calls the Mexican herb stronger, sharper and more pungent than Origanum,⁴ and ATK’s tasters found Mediterranean oregano milder and faintly sweeter, and the Mexican type stronger, with a hint of menthol.⁶

Why two unrelated plants share a name

“Oregano” names a flavor, not a genus. A 2020 review of oregano chemistry notes that the name is applied to several Origanum species and to plants in other genera, Lippia among them.⁵ What links them is the oil. Mexican oregano’s family tie is to lemon verbena, Aloysia citrodora, which Kew also places in Verbenaceae;¹⁰ oregano’s relatives are mint, thyme and marjoram.

The chemistry, sample by sample

Each figure belongs to the oil it was measured on. These are essential-oil figures from different studies, not measurements of dried leaf from a jar, and they should not be merged into a single comparison.

On these figures, Mexican oregano leans on thymol and Mediterranean oregano usually leans on carvacrol. ATK notes that both plants contain carvacrol.⁶ A 2021 review of L. graveolens also names β-caryophyllene and p-cymene among its terpenes.¹¹ We found no study that measured both herbs side by side under the same conditions.

The differences that change a dish

Strength

The Mexican herb is the stronger one, by both PROSEA’s account and ATK’s tasting.⁴⁶ In a dish built around a teaspoon of dried oregano, that is the difference most cooks will notice.

Which cooking it belongs to

PROSEA calls Mexican oregano an important spice in Mexico and Central America.⁴ US extension recipes use it in chile cooking: NMSU’s New Mexico red chile sauce adds crushed dried Mexican oregano near the end and simmers it another 5–7 minutes,⁸ and a University of Tennessee white chicken chili calls for 2 teaspoons.¹² By common practice it also goes into pozole, beans, salsas and adobos, often with cumin and dried chiles.

Oregano is the herb of Italian and Greek cooking. Britannica calls it essential in Italian pizza and pasta sauces, Greek salads and gyros, and a key ingredient in Mediterranean and Middle Eastern cooking.³

Long cooking

Both are used dried, and dried oregano copes well with heat. America’s Test Kitchen classes oregano among the hearty herbs that go in early,¹³ and in its dried-versus-fresh tests dried oregano held up reasonably well in dishes with more than 20 minutes of cooking and a good amount of liquid.¹⁴ In chili, dried oregano was the tasters’ favorite over fresh.¹⁴ The University of Delaware’s general rule for long simmering is to add herbs during the last 45 minutes.¹⁵ We found no test of how Mexican oregano behaves over long cooking.

Can one stand in for the other?

Yes, in most cooked dishes. ATK tried both kinds in tomato sauce and in mojo-marinated skirt steak and noticed only minimal differences.⁶ Maggie Unzueta of Mama Maggie’s Kitchen, writing about Mexican cooking, says most cooks of Mexican food use regular oregano all the time.¹⁶

• Oregano in place of Mexican oregano (Attributed). RawSpiceBar’s Joseph Rosenblatt says to start with 1.5 times as much regular oregano; the same article elsewhere suggests about 25% more, so the merchant’s own advice runs from 1 1/4 to 1 1/2 times.¹⁷ Given ATK’s finding of minimal differences,⁶ starting with an equal amount and adding the rest after tasting is the cautious route. See Mexican oregano substitutes.
• Mexican oregano in place of oregano (Method). No published ratio was found. Because the Mexican herb is the stronger,⁴⁶ start with about three quarters of the oregano amount and taste. Our oregano substitutes page uses the same starting point.
• Rub it first. Unzueta suggests rubbing dried oregano between your hands to release its flavor,¹⁶ and the University of Delaware suggests crushing dried herbs for the same reason.¹⁵

Where the swap shows most is a raw salsa or a quick dish where the herb is not cooked down (editorial).

What isn’t known

• No published measurement compares the flavor strength of the two herbs. Every ratio above is a rule of thumb.
• A widely repeated description gives Mexican oregano a licorice note. No source reviewed here mentions licorice; ATK’s tasters reported a hint of menthol instead.⁶
• The common claim that Mexican oregano is used as a tea herb could not be traced to a source we could open.
• The claim that oregano most likely originated in Greece does not match Kew, which gives a native range from Macaronesia to China.²

Related

• Profiles: Mexican oregano, oregano, lemon verbena, marjoram
• Substitutes: Mexican oregano substitutes, oregano substitutes
• Comparisons: marjoram vs. oregano, oregano vs. thyme, cilantro vs. oregano, fresh oregano vs. dried
• Best spices for chili and too much oregano?