The sassafras tree, a native of North America, has a long history of use both as flavoring and medicine. The oil extracted from its root was one of the original constituents of herbal root beer. As medicine, it was used to treat influenza and other fever-producing infections, as well as arthritis, urinary tract infections, and digestive disorders. It was also commonly used as a “spring tonic” or “blood purifier.”
However, in the 1960s, it was discovered that sassafras oil contains high levels of a liver toxin named safrole. ^ ^ ^ ^ When given to animals, safrole causes liver cancer, and even a single cup of sassafras tea contains dangerous levels of the substance.
Because of this, sassafras has been banned for human consumption. Only safrole-free products can be sold; however, there may be other carcinogens in sassafras besides safrole. ^ Sassafras oil is also immediately toxic; a few drops can kill an infant, and a teaspoon can cause death in an adult. ^ For all these reasons, we strongly recommend against the use of sassafras for any purpose.