Gumbo filé is the powdered, dried leaves of the sassafras tree. This tree is native to the east coast from Maine to Florida and stretches west along the Gulf Coast to Mexico. The Choctaw Indians first used sassafras as a seasoning. When the French Canadians went south to Louisiana, they quickly adapted the Choctaw methods of using sassafras in cooking.
Sassafras roots use to be an essential ingredient of root beer.

Gumbo filé powder is the essential flavoring and thickening ingredient of gumbo and can also be used to perk up sauces and gravies. Gumbo filé is generally added after the dish has been removed from the heat, but before it cools as it becomes stringy when cooked.