Sassafras oil is an oil that comes from the bark of sassafras trees, which are native to eastern North America and eastern Asia. It is toxic and contains safrole, which is a known cancer-causing substance.
The use of sassafras oil and safrole in the food and drug industries has been banned in the United States by the Food and Drug Administration since 1960. Before the ban, sassafras oil and other sassafras extracts were widely used as food additives and flavors. It was also used in the treatment of various illnesses including sexually transmitted diseases and menstrual disorders. Sassafras extracts from which safrole has been removed are still used in the U.S. to make teas and as a flavoring for root beer.