The University of Maryland Medical Center says children, the elderly, pregnant or breastfeeding women should avoid using comfrey in any form.

Don’t mix comfrey with medications that are hard on your liver, i.e. acetaminophen, and avoid using it with other herbs “known” to cause liver problems, such as kava, skullcap, and valerian.

External use: Mill the pieces of root, mix the powder with hot water and a few drops of the oil, spread them on linen fabric and swathe area while still warm.

Pour 1-2 teaspoons of tea in 1/4 liter of water overnight.

In the morning we heat the mixture, strain it and drink it in small quantities 1-2 times a day