Gumbo Filé Powder: What It Is, How to Use It and Why It Is Legal

Spotted a jar of green powder among the table condiments at a Creole or Cajun gumbo spot? That’s filé: dried, finely ground sassafras leaf, and it does two jobs. Sprinkled on late, it seasons a gumbo with a green, earthy, thyme-like flavor. Cooked in, it thickens the pot, and if you add it too early it goes stringy and ropy. It comes from the same tree as banned sassafras oil, and it’s still legal to sell.

At a glance

What filé is

Filé is made by harvesting sassafras leaves, drying them, and pounding them to a fine powder. Morgan Randall, profiling the Louisiana filé maker John Oswald Colson and his protégé Dustin Fuqua, describes leaves picked by hand, dried over two to three weeks, and ground with a pile and pilon into a bright green powder.³

The tree, Sassafras albidum, is native from southeastern Canada through the central and eastern United States. For the tree itself, its root, and the story of sassafras tea and root beer, see sassafras.

Flavor and the compounds behind it

Robert Caldwell, writing in the Louisiana encyclopedia 64 Parishes, says filé added as a seasoning gives a sweet, earthy, peppery and thyme-like flavor. Green leaves dried in the dark, he adds, taste lemony and coriander-like with a grassy undertone, while commercial filé dried in sunlight is a duller green.⁴ Katzer describes the leaves’ aroma as weak but fresh and lemon-like.

The leaf isn’t very oily. Katzer gives the leaves about 0.4% essential oil, of which roughly 45% is safrole and 30% camphor, with α-pinene, citral and phellandrene in smaller amounts.¹ You’ll see a figure of 2–3% oil for the leaves floating around, but it doesn’t match. Katzer’s higher figures are for the root (about 2%) and especially the root bark (about 8%). The root beer flavor people link with sassafras came from the root oil, not the leaves.¹

Origin and history

Filé has Choctaw roots. Caldwell writes that many Choctaw foods once used powdered sassafras, and gives the tree’s Choctaw name as iti kʋfi. Randall gives the Choctaw word for the plant and its powder as kombo, and says the Choctaw gathered and dried the leaves and used the powder to thicken and flavor soups.³ Today, Creole and Cajun restaurants serving gumbo often set filé out with the table condiments. You’ll often hear how and when Louisiana’s Acadian settlers took up filé, but we found no source that documents it.

Sassafras had a separate career as medicine. Its bark became one of the Jamestown colony’s main exports, and the Spanish physician Nicolás Monardes called it a universal remedy for all manner of diseases.⁵ That’s a history of belief, not evidence. You’ll also read that sassafras was the colonies’ second-largest export after tobacco. We couldn’t trace that.

How to use filé

With filé, timing is everything:

• For flavor, add it late. Caldwell says you can add filé as a seasoning to a gumbo, soup or stew after turning down the heat, and that it’s most often sprinkled on as a finishing garnish. Katzer likewise has it stirred in right before serving.
• Cooked in, it thickens and turns stringy. Added early, filé gives a viscous, slimy, stringy texture that Caldwell says looks like ropes when poured. Adding it after the heat comes down, he says, keeps the dish from going ropy.⁴

Filé is one of three common gumbo thickeners, along with okra and a flour roux. Caldwell writes that filé gumbos and okra gumbos were traditionally separate dishes, partly because okra was seasonal, and that you can make a filé gumbo without a roux.⁴ Randall describes filé as what cooks reach for when okra is out of season.

In the sources we read, gumbo is filé’s main use. You’ll sometimes see it mentioned for étouffée and other dishes, but none of the sources we opened documents that. For the rest of the Louisiana spice shelf, see Cajun seasoning, Creole seasoning, Cajun vs. Creole seasoning, okra spices, thyme and bay leaves.

Buying and quality

• Color. Randall contrasts bright green homemade filé with the sawdust-like color and texture of commercial filé, and Caldwell links commercial filé’s duller green to drying in sunlight.³⁴
• Pure or blended. Some filé is blended with other herbs, like bay leaves, oregano, thyme and basil, so check the label if you want sassafras alone.
• Red filé. Made from red fall leaves, it lacks the chlorophyll of green filé and tastes different.

We found no grading standard for filé.

Storage

We found no published shelf-life figure for filé powder from a regulator or standards body. Keep it sealed, cool and dark, and judge it by color and smell.

Safety and regulation

Sassafras is regulated because of safrole, a compound in its oil.

• United States. The FDA treats food containing added safrole or oil of sassafras as adulterated, citing an order of December 3, 1960.⁶ Sassafras leaves are still on the FDA’s list of natural flavoring substances, with the limitation “safrole free.”² We found no FDA statement that names filé powder, and no published measurement of the safrole in retail filé.
• Why safrole matters. The National Toxicology Program lists safrole as reasonably anticipated to be a human carcinogen, on evidence that it caused liver tumors in two rodent species. It reports no studies of people exposed specifically to safrole.⁷ Katzer considers the leaves and filé generally harmless at cooking amounts because their safrole content is low, while strongly discouraging use of the root. That’s his call.¹
• European Union. Safrole can’t be added to food as such, and limits apply in compound foods (for example 25 mg/kg in soups and sauces), but those limits don’t apply when the only flavoring ingredients added are herbs and spices.⁸

Health claims

Filé sometimes gets promoted for kidney stones, high blood pressure, arthritis and gout, or for anti-inflammatory compounds in its oil. We found no credible source for any of those effects. Katzer traces the name sassafras to Latin for “stone breaker,” after an old use against kidney stones that he calls obsolete.¹ We’re not claiming filé treats or prevents any condition.

Substitutes

Okra or a dark roux can take over filé’s thickening job, but neither one gives you its flavor. See gumbo filé substitutes, sassafras substitutes and saffron vs. sassafras.