Basil vs. Parsley: The Lead Herb and the Supporting One

A handful of basil defines a pesto; a handful of parsley brightens a stew without taking over. That’s the real split between these two finishing herbs: basil is usually the flavor of a dish, and parsley more often backs one up. They come from different plant families and bring very different amounts and kinds of aroma. Basil oil is built on methyl chavicol (estragole), a sweet-spicy compound, while parsley has only a little leaf oil and a warm, slightly bitter flavor. And of the two parsley leaf types, flat-leaved has the stronger flavor, though curly-leaved carries more oil.¹

Side by side

Looking for relatives? Oregano is in the mint family with basil, and cilantro is in the parsley family.

How much aroma, and from what

The oil figures below come from different works and weren’t measured the same way, so read them for direction, not as a precise ratio.

Britannica gives a much lower figure for basil, 0.1%, also with no stated basis, so basil’s oil content itself is disputed.⁶ The sources do agree on the compounds, though: basil and parsley share no lead compound, and neither tastes like the other.

PROSEA also says flat-leaved parsley has the stronger flavor of the two leaf types,¹ the reverse of what the oil-content figures alone might suggest. PROSEA doesn’t say why.

The differences that change a dish

Role

Basil leads and parsley supports. A handful of basil defines a pesto or a tomato salad. A handful of parsley brightens a stew, a sauce or a plate of fish without taking over. Parsley goes with fish, meats, soups, sauces and salads, and curly-leaved parsley is commonly used for garnishing and seasoning.

Fresh, dried and heat

You’ll often read that dried basil is worth using and dried parsley isn’t. America’s Test Kitchen puts both in the same group of herbs that lose a lot of flavor when dried,³ and its tests describe delicate herbs, basil and parsley among them, as more volatile.⁷ Both are among the delicate herbs best added in the last minute or two of cooking. For long-simmered dishes, the University of Delaware’s gentler rule is to add herbs during the last 45 minutes.⁸ See dried basil vs. fresh and fresh parsley vs. dried.

Which parsley

There are three cultivated groups: curly-leaved parsley with compact branches and curled leaf blades, flat-leaved parsley with more open branches and flat leaf blades, and turnip-rooted parsley, a sturdier plant with long fern-like leaves. For cooking, flat-leaved has the stronger flavor of the leaf types.¹ See Italian parsley vs. curly parsley.

Can one stand in for the other?

For looks, sometimes. For flavor, rarely.

• Basil in place of parsley. Ratio (Method): Our parsley substitutes page suggests starting with about half the parsley amount and tasting, and keeping basil to Italian dishes where it already belongs. A chiffonade of basil gives you a similar green finish, but basil will stand out where parsley would blend in.
• Parsley in place of basil. Parsley adds color and a fresh, slightly bitter note, but none of basil’s sweetness or anise. Ratio (Method): In a tomato sauce or salad, start with the same amount and accept that it’s a different dish. A parsley pesto is its own sauce, not a stand-in.

Safety notes

Neither herb is a worry at normal kitchen amounts, but each comes with one thing to know:

• Parsley and warfarin. MedlinePlus lists parsley among foods that can affect warfarin. Its advice isn’t to avoid these foods but to keep amounts small and steady.⁵ Britannica warns that parsley seed oil, or large amounts of other parsley preparations, can cause serious reactions. That’s about concentrated preparations, not leaves in your cooking.⁹
• Basil and estragole. Germany’s BfR names basil-containing pesto among foods that may contain high amounts of estragole and related compounds.⁴ The basil profile covers what regulators have concluded.

What isn’t known

• PROSEA puts basil’s essential oil content at about 1.5% and Britannica at 0.1%, and neither states a basis.²⁶
• We couldn’t trace the often-repeated description of flat-leaf parsley leaves as “rosettes” to a source.

Related

• Profiles: basil, parsley, cilantro
• Parsley substitutes
• Comparisons: cilantro vs. parsley, oregano vs. parsley, chervil vs. parsley, flat-leaf vs. Italian parsley, basil vs. oregano, basil vs. cilantro
• Cooking with basil, how to store basil, how to store parsley