Please Note: Professional herbalists and naturopathic physicians take a very different stance on comfrey use from the established authorities. Many herbalists and NDs feel it's safe to use comfrey as long as you don't use it continually, long-term. Therefore, they recommend you use it in moderate doses for 3 to 6 months, then take a break of 1 month to allow the liver to cleanse properly, then resume use for 3 to 6 months, etc. as needed. Comfrey has become one of the FDA's targeted substances - likely due to its effectiveness, so when you do your research, keep that in mind.