Sassafarin (sp?) shown to be a carcinogen. It's in the roots, from which the tea made.
Sassafras has three different leaves on one tree: unilobular, mitten and trilobe. Pick a leaf. Taste the stem. It should have a citrus flavor. Put that altogether, and you will be sure what you have is a sassafras. If I saw the bark, I could tell you by that, too.