Fresh comfrey leaves are rich in vitamins A, B12 and C and in the minerals calcium, phosphorous and potassium. Comfrey also has a higher protein content than any other vegetable.
The herb is at present the subject of extensive scientific research, and until conclusive evidence is available comfrey should only be used externally.
Dried comfrey leaves used to be used to make an infusion that was recommended for soothing away coughs and bronchitis. As comfrey tea stimulates healthy cell division, it was traditionally a health drink for older people, though it should be drunk for a short time only, rather than an indefinite period, and always under medical supervision. A week infusion of comfrey is also prescribed for bathing minor burns and scalds as it helps to heal the skin.