When taken by mouth: Comfrey is LIKELY UNSAFE for anyone when taken by mouth. It contains chemicals (pyrrolizidine alkaloids, PAs) that can cause liver damage, lung damage, and cancer. The FDA has recommended that all oral comfrey products be removed from the market.

Is comfrey safe to use?

It's considered unsafe, due to the pyrrolizidine alkaloids that comfrey contains. These are dangerous chemicals that can cause cancer, severe liver damage, and even death when you consume them. For this reason, the Food and Drug Administration and European countries have banned oral comfrey products.

Are comfrey plants dangerous?

Comfrey has toxic substances that can cause severe liver damage and even death. You should never take comfrey by mouth. The toxic substances in comfrey can be absorbed by the skin. Even creams and ointments should be used for only a short time, and only under a doctor's supervision.