The herb contains alkaloids (I'm reading from a book) which can cause liver damage. It is only present in minute amounts, or sometimes not at all, in the aerial parts from which the tea is made. Most is in the root. I'd suggest, given the taste and with the advised caution, you don't make it your main drink of the day! (I've made comfrey liquid manure, and I have never smelt anything so disgusting!) The book recommends applying comfrey ointment, cream or infused oil onto fractures. Not onto broken skin, though. I hope the tea has helped, because it does have anti-inflammatory properties.

Andrea