Coltsfoot is the plant Tussilago farfara, a member of the daisy family (Asteraceae). Coltsfoot is a perennial herb that grows to a height of 4-10 inches (10-25 cm). The stem is covered with white, downy fibers. Its leaves are hoof-shaped, and the flowers are yellow. The leaves, flowers, and occasionally the root are used medicinally.
Coltsfoot is a tough, invasive plant that lives in marginal soil, wasteland, roadsides, and sand dunes. In some areas coltsfoot is considered an undesirable weed. Although native to Europe, coltsfoot grows wild in North America and the temperate parts of China. Other names for coltsfoot are cough wort, horsefoot, horsehoof, bull's foot, ass's foot, foal's foot, British tobacco, butterbur, field hove, and flower velure. In Chinese it is called kuan dong hua.
Coltsfoot has been used as a cough remedy in both Western herbalism and traditional Chinese medicine for at least 2,500 years. Coltsfoot was such a well-known and well-respected herb in eighteenth century France that apothecary shops advertised their presence by painting a picture of the herb on their signs. Chinese herbalists prefer to use the flower and flower buds, while Western herbalists most often choose to use the leaves.
Coltsfoot is recommended to treat:
- dry, hacking cough
- laryngitis and hoarseness
- lung cancer symptoms
- mouth and throat irritations
- sore throat
A decoction (boiling the herb down to a concentrated broth or tea to be taken internally) of coltsfoot root is sometimes used to induce sweating. Externally, a poultice of flowers is sometimes applied to the skin to treat eczema , stings, bites, and skin inflammations. Sometimes coltsfoot leaves are smoked to relieve cough.
Modern scientific investigation shows that coltsfoot contains a substance called mucilage (about 8%) that coats and soothes the throat. It is the presence of this substance that appears to make coltsfoot so effective in treating coughs and respiratory problems. Coltsfoot tea also appears to help clear the airways of mucus in some animal studies. Smoking coltsfoot will probably do more to irritate the throat than to soothe it.
Inhaling steam from a pot of boiling coltsfoot leaves is likely to produce little effect because so little of the medicinal material will reach the throat. The German Federal Health Agency's Commission E, established in 1978 to independently review and evaluate scientific literature and case studies pertaining to herb and plant medications, has approved the use of fresh or dried coltsfoot leaf in products to treat dry cough, hoarseness, and mild throat or mouth inflammations.
Despite evidence that coltsfoot does generally work, it is not without its problems. The leaves, and to a greater degree the buds and flowers, contain compounds called pyrrolizidine alkaloids. These compounds are known to damage the liver. They can cause liver cancer with extended exposure and may also cause the blood vessels of the liver to narrow dangerously. In one laboratory study, rats fed a diet of coltsfoot flower developed a high rate of cancerous liver tumors.
In the United States, the Food and Drug Administration (FDA) has labeled coltsfoot an herb of "undefined safety." Coltsfoot leaf also falls under some legal restrictions in Austria. German authorities, however, simply recommend that preparations containing coltsfoot leaf should not be taken for more than four to six weeks each year. There is, however, fairly unanimous agreement that the level of pyrrolizidine alkaloids in coltsfoot flowers is much higher than the level found in the leaves, and that medicinal preparations that use the flower or flower bud should be avoided. Some American herbalists are recommending that the internal use of coltsfoot be discontinued as a precaution until further research clarifies the risks involved.
Coltsfoot leaves are harvested in early summer and can be used fresh or dried. In China, the flower heads are dug up in winter, before they emerge from the ground. When the root is used, it is harvested in the autumn.
Coltsfoot is most commonly prepared as a tea. It can also be made into a cough syrup when combined with licorice, thyme , or black cherry. Commercial preparations are also available.
The safest course is to avoid the internal use of coltsfoot. Pregnant and nursing women and children under the age of six should not be given coltsfoot. People who choose to use coltsfoot should avoid ingesting more than 1 gram of pyrrolizidine alkaloids daily. However, accurate measurement of pyrrolizidine alkaloids is difficult and this information is not easily available to many consumers.
Coltsfoot is believed to increase the incidence of liver damage and cancerous liver tumors in both laboratory animals and humans.
There are no studies of the interactions of coltsfoot with conventional pharmaceuticals or other herbal remedies.
Chevallier, Andrew. Encyclopedia of Medicinal Plants. New York: DK Publishing, Inc., 1996.
PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company, 1999.
Peirce, Andrea. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: William Morrow and Company, 1999.
Weiner, Michael and Janet Weiner. Herbs that Heal. Mill Valley, CA: Quantum Books, 1999.
Plants for a Future "Tussilago farfara." http://www.pfaf.org.