As this subject surfaces often and there are known 'nay sayers' that interrupt such often do be aware that this present area is 'off limits' to known persons. Feel free to discuss this subject here and now. This is not medical advice, we are not medical practitioners, anything stated here is just the opinion of the individual poster. Do not use anything said here in place of professional medical advice. If you can provide any site addresses to back up your words, do post them. Please display your source of information. I can speak for the effects of comfrey, in a suave form as to it being something that helps heal bone pain via a broken rib via a horse kick. Comfrey is also known as 'bone knit', it has been used for many decades as an external pain reliever for broken bones, such is mentioned often in the sites listed in the links library, under herbs and their applications.