Sassafras is a genus of three species of deciduous trees in the family Lauraceae, native to eastern North America and eastern Asia.
The roots of sassafras can be steeped to make tea, and were used in the flavouring of traditional root beer until being banned for mass production by the FDA. Laboratory animals that were given oral doses of sassafras tea or sassafras oil that contained large doses of safrole developed permanent liver damage or various types of cancer. In humans, liver damage can take years to develop and it may not have obvious signs. Along with commercially available sarsaparilla, sassafras remains an ingredient in use among hobby or microbrew enthusiasts.
In 1960, the FDA banned the use of sassafras oil and safrole in commercially mass produced foods and drugs based on the animal studies and human case reports. Several years later, sassafras tea was banned, a ban that lasted until the passage of the Dietary Supplement Health and Education Act in 1994. Sassafras root extracts which do not contain safrole or in which the safrole has been removed are permissible, and are still widely used commercially in teas and root beers.
Filé powder, also known as gumbo filé, is a spicy herb made from the dried and ground leaves of the sassafras tree (Sassafras albidum), native to eastern North America. Choctaw Indians of the American South (Florida, Mississippi, Alabama, Louisiana) were the first to use dried, ground sassafras leaves as a seasoning, what is now called filé, or gumbo filé, used in Creole cooking. It is used in the making of some types of gumbo, a Creole and Cajun soup/stew often served over rice; other versions of gumbo use okra or a roux as a thickener instead. Sprinkled sparingly over gumbo as a seasoning and a thickening agent, it adds a distinctive, earthy flavour and texture. Filé can provide thickening when okra is not in season. Filé translates to "string", suggestive of the powder's thickening ability.
Unlike sassafras roots and bark, the tree's leaves, from which filé is produced, do not contain a detectable amount of safrole. This is significant because safrole is regarded by the U.S. government to be a product used in the manufacturing of MDMA and MDA, as well as a weak carcinogen. The relationship between safrole and sassafras may be the origin of the widely-reported belief that filé powder has a questionable effect on human health.