These are the varieties traditionally grown for medicinal and forage use.
PLEASE NOTE: Due to low level concentrations of pyrrolizidine alkaloids found in the leaves and roots, many authorities no longer recommend using comfrey internally. These alkaloids are reported to have caused liver damage when consumed over a long period of time. External use is safe, however, because the offending alkaloids are not absorbed through the skin. Have the dangers of internal use been exaggerated out of proportion? We think so. This is a herb that has been used for hundreds, if not thousands of years. We suspect problems with comfrey emerged in recent decades when it was used as a food and nutritional supplement or it was used for long term treatment of chronic health problems. It seems likely that traditional comfrey use was never long term; instead, it was, and is, best suited, we believe, for short-term medicinal use. As a bone and tissue wound healing herb, for example, it is incredibly effective. It is a shame that some governments have chosen to overreact to a handful of published reports of liver damage in patients who ingested comfrey in large quantities or over lengthy periods. In Canada all comfrey products were banned in 2003, although it is still legal to grow your own comfrey for personal use. For obvious reasons, we at Richters cannot recommend that anyone use comfrey medicinally – at least not without guidance from a professional health care provider.