Symphytum officinale, Bruisewort, Knitback, Knitbone, Boneset, Slippery Root, Bruisewort, Ass Ear, and Blackwort.
Comfrey leaf has a long history of use to promote the healing of bones and wounds, as well as internal use to treat a wide variety of ailments from arthritis to ulcers. Dioscorides recorded how it was used in treating the armies of Alexander the Great, and Pliny the Elder also makes mention of its great many uses. Its use in Chinese traditional medicine spans over 2000 years. All Materia Medica from the Middle Ages forward carried descriptions on the uses of comfrey. Comfrey bathes were very common during the Middle Ages. They were especially popular with women who took them before they were married in order to repair their hymen and thus restore their virginity. Comfrey is widely known as "one of nature's greatest medicinal herbs", and has appeared in the U.S. Pharmacopoeia, as well as in herbals and compendiums around the world. Recently, reports of the toxic effects of pyrrolizidine alkaloids in comfrey have led some herbalists to be wary of using it internally. PAs in extremely large doses or over long periods of time may cause potentially fatal damage to the liver. Many leading herbalists and traditional healers question the warnings, pointing to laboratory tests that show only minute levels of PAs in random samples of comfrey preparations. One of the most common uses of comfrey leaf is in an ointment or a poultice applied to sprains, broken bones and other wounds, where it promotes rapid healing of both skin lesions and bone breaks.
tannin, rosmarinic acid, allantoin, steroidal saponins, mucilage, inulin, pyrrolizidine alkaloids, Gum, Carotene, Glycosides, Sugars, Beta-sitosterol, Triterpenoids, Vitamin B-12, Protein, Zinc.
The main healing ingredient in comfrey leaf appears to be a substance called allantoin, which encourages the rapid growth of cells.
Paste, ointment, tincture, decoction, poultice and in cosmetics.
Research seems to bear out the claims for the healing properties of comfrey leaf. In one major European study, an ointment based on comfrey root proved more effective at relieving both pain and swelling in 142 patients with sprained ankles. In another study with over 300 participants showed that comfrey leaf treatments of varying types (ointments, salves, compresses and other topical applications), were very effective in treating eczema, dermatitis, viral skin infections and ulcers of the lower leg. More recent research in the United States has shown that allantoin, one of comfrey's main constituents, breaks down red blood cells, which could account for its ability to help heal bruises and contusions as well as promoting the growth of muscle, cartilage, and bone growth.
With regards to the warnings that comfrey can cause cancer and liver disease, most herbal practitioners point out that those results were from studies that isolated the pyrrolizidine alkaloids and fed or injected them into animal subjects in doses far higher than any typical usage of comfrey leaf, and that comfrey leaf has been regularly ingested by thousands of people around the world without reported ill effects.
Not recommended for internal use. Not to be used while pregnant. Not to be applied to broken or abraided skin.
Comfrey was widely used and recommended until the mid-1980s, when reports began to surface about the possibility of liver damage from the pyrrolizidine alkaloids that some plants contain. In 2001, the FTC and FDA combined to issue an injunction against products containing comfrey that were meant for internal use.
This view has been countered by herbalists, who state that common comfrey, the plant most often used for medicinal purposes, contains only negligible amounts of those alkaloids. In fact, one laboratory study of three different sources of comfrey found no pyrrolizidine in one sample, and only negligible amounts in the other two. Still, many herbalists recommend that comfrey preparations should not be taken internally because of the possibility of liver disease and damage. Comfrey should also not be used by pregnant or nursing women.