You're VERY WELCOME, Elaina!! Once AGAIN, this is a Case, where the F.D.A. has been spreading MISINFORMATION about a WONDERFUL GOD-GIVEN HEALING Herb!!
Just as they did with Sassafras and a some other Herbs (i.e. - Lobelia, Poke Root, ...), the F.D.A., in their Laboratories, ISOLATED one Constituent (Alkaloid) and gave it to some Rats at a Dosage, that was 1000 or MORE times the NORMAL Dosage, and the Rats got CANCER! A Human would have to take MANY pounds of the Herb at ONCE to get that SAME Dosage, but even then there are other Constituents in the Herb, which PROTECT a Person from ANY ILL Effects of ANY of the other Constituents! Their Findings are NOT Scientific PROOF that Comfrey or Sassafras or ... is BAD for you or ANY of us!!
By the way, if you don't own this Book, I recommend that that you get it, "The School Of Natural Healing" by John R. Christopher, M.H., N.D.. Dr. Christopher originally taught Herbal Therapy to Dr. Schulze and then afterwards Dr. Schulze became Dr. Christopher's No. 1 Professor at his "School Of Natural Healing" for MANY years, before he went UNDERGROUND with his "LAST CHANCE CLINIC" in Malibu, CA!