In traditional Creole and Cajun cuisines of Louisiana, Gumbo File Seasoning powder is used for its subtle, floral flavor and unique thickening properties. As a thickener, it can be used on its own or in addition to roux and okra. Gumbo File Seasoning is generally added at the end of the cooking process, or stirred into a single serving of hot seafood gumbo. Gumbo File Seasoning is made from the dried leaves of the sassafras tree of the eastern United States. American Indians pounded sassafras leaves into a powder and added them to soups and stews. Ingredients: Sassafras leaves.