When I lived in Virginia while I was writing The Natural Mind, I was intrigued when locals told me about sassafras. Because this shrub or small tree is the first plant to come to life in the spring, they would drink tea made from its root as a tonic to "purify the blood of winter stagnation." When March rolled around, I kept my eye out for sassafras, whose twigs are easy to spot because they remain green all winter. When the ground was soft enough to dig, but before the bush had developed any leaves, I went after a bit of sassafras root. As my shovel hit the root, the air filled with a zingy fragrance that smelled to me like essence of spring. When I boiled a piece of the white root, it produced a deep red tea that tasted so good I began drinking a cup every day. After a few weeks, just as leaves began to appear on the bush, the tea stopped tasting good, and I lost my desire for it. It was as if the plant told me the right time to drink it had passed.
Sassafras (Sassafras albidum) grows throughout the eastern United States and as far west as Texas. Extracts of the root and root bark were used by Native Americans and the early European explorers of North America, who believed them to be a miracle cure. The essential oil from the root bark and twigs were widely used to flavor root beer and candy and to scent soap and perfume as well as for making tea.
However, the volatile oils found in the bark of the root of the sassafras plant are 80 percent safrole, a compound that turns out to be carcinogenic in laboratory animals. Studies have shown that rats and mice injected with large amounts of safrole have trouble walking and show signs of nervousness and confusion as well as difficulty with body temperature regulation. Long-term exposure to safrole can cause liver cancer in laboratory rats. For these reasons, in 1960 the FDA banned food additives containing safrole. Health authorities in Canada followed suit.
Perhaps the biggest effect of this ban has been to eliminate the use of sassafras root in the making of root beer. Today, sassafras can be used as an ingredient in root beer only if the safrole has been removed through a laboratory extraction process. Small amounts of safrole also occur naturally in black pepper, star anise, nutmeg, witch hazel, and basil, all of which are safe in the amounts usually consumed. Another culinary use of sassafras is for making the Creole spice filé (dried sassafras leaves ground to a fine powder) which thickens gumbo, when okra is not in season.
Consuming moderate amounts of safrole in plant products (such as sassafras tea) is not comparable to injecting large amounts of the pure chemical into the abdomens of rats. A search of the medical literature for sassafras tea shows only one report of an adverse effect: excessive sweating in a man who began drinking it.
If you're living around the trees and want to drink the tea for a few weeks in the early spring, I see no reason not to try it, but I'm also unaware of any documented health benefits of sassafras tea.
Andrew Weil, M.D.