Danno, as always, thanks for the info, we need differing opinions so we won't get tunnel vision. I'll have to very much disagree with them folks. (but I'll keep it in mind as well) My grandparents along with my great grandmother raised me. My grandfather was "THE" jack of all trades in the community during the mid 1900's. He was a lot of stuff, veterinarian, butcher, meat curer, farmer, carpenter, other stuff, and an herbalist. He could cure just about any sick animal.
He had a salve that all I can tell you is it turned blue-ish yellow when applied on you. He used it on all the livestock and all the kids. I can remember folks talking about his salve and how good it healed. All that knowledge went to the grave with him. He managed to teach me a couple of things but I was more interested in smoking pot, drinking, and womanizing in my teens. But I distinctly remember sassafras as part of the medicine chest. I remember hearing my grandma telling him to go get some more roots, one of the kids has a cold, they'll all have it next thing you know.
He died of a heart attack at 75, grandma was 95, and my great grandma was a little over 100. The older I get the more suspicious I get. I can't help but questioning anything the gov't, or a college, or a drug company says. But the main reason is it was normal for folks to drink it when I was growing up, and I drank it as well. Most of those folks died of old age around here.