Cajun Land Gumbo File 1.1 oz. A staple for gumbo lovers everywhere! Made from only the finest ground sassafras leaves, our Gumbo file thickens and flavors gumbos, soups, and stews. Add to your pot when it’s nearly done or add a dash to your serving bowl before eating. Gumbo file thickens and flavors gumbos, soups, and stews. Add to you pot when it's nearly done or add a dash to your serving bowl before eating.