檫树根为樟科植物檫树Sassafras tsumu Hemsl.的根。含挥发油, 主要成份为黄樟醚 (Safrole)
https://en.wikipedia.org/wiki/Safrole
Carcinogenicity
Studies in the 1960s indicated that safrole was carcinogenic, causing permanent liver damage in animals. Consequently the US Food and Drug Administration (FDA) banned sassafras and safrole for human consumption.[5]
http://www.med126.com/pharm/2010/20100123235854_167993.shtml