Comfrey Leaf by the weighed ounce.
The following is taken from a reputable web site but please do your own investigation:
The chief and most important constituent of Comfrey root is mucilage, which it contains in great abundance, more even than Marshmallow. It also contains from 0.6 to 0.8 % of allantoin and a little tannin. For its demulcent action it has long been used in lung troubles and whooping cough. The root is more effectual than the leaves and is the part usually used in cases of coughs. It has been used for all pulmonary complaints, consumption and bleeding of the lungs. Effective for eczema and dry skin. The infused oil has been used externally for sprains, swelling and bruising. Comfrey root and leaves have been used externally as a poultice to heal boils and abscesses. Caution: In 2001 the U.S. government warned manufacturers of dietary supplements that comfrey, an herb in some of their products, is known to cause liver damage.