Family: Boraginaceae, Symphytum officinale L.
Source: Simon, J.E., A.F. Chadwick and L.E. Craker. 1984.
Herbs: An Indexed Bibliography. 1971-1980. The Scientific Literature
on Selected Herbs, and Aromatic and Medicinal Plants of the Temperate
Zone. Archon Books, 770 pp., Hamden, CT.
Comfrey, Symphytum officinale L., is a hardy perennial
herb native to Eurasia and naturalized in North America. Also
known as common comfrey, blackwort, boneset, bruisewort, gum plant,
healing herb, salsify, and slippery root, this erect-growing herb
can reach a height of one meter. Characteristically covered with
a prickly pubescence, the plant develops flowers colored from
white to purple, a thick, externally black root, and relatively
The reported life zone of comfrey is 6 to 25 degrees centigrade
with an annual precipitation of 0.5 to 2.7 meters and a soil pH
of 5.3 to 8.7 (4.1-31). The plant grows best in a moist environment
and is found wild along rivers.
Although long grown for medicinal and nutritional properties,
comfrey is sometimes used as an ornamental and culinary herb.
Fresh leaves are used as a salad green, and the dried roots can
be combined with dandelion and chicory for use as a noncaffinated
coffee. Symphytum officinale L. cv. variegatum is
a commercially available ornamental with white variegated leaves.
Comfrey can be used as a fodder crop for livestock.
The roots and leaves of the plant have been used medicinally as
an astringent, demulcent, emollient, and expectorant, and against
digestive disturbances, ulcers, internal inflammations, bleeding,
and cancer (14.1-13). The "healing herb" name comes
from the traditional external application of comfrey to heal injured
tissue and bones. The plant root has a large content of mucilage,
allantoin, symphytine, echimidine, isobauerenol, -sitosterol,
tannins, and lasiocarpine (11.1-136). The tannins are undoubtedly
responsible for astringent properties of the plant parts, and
the allantoin in the mucilage accounts for the demulcent activity.
The pyrrolizidine alkaloids are potentially toxic, known to cause
hepatotoxicity and to be carcinogenic (11.1-154). Whether the
small to moderate amounts ingested by humans are harmful is still
under debate. Comfrey leaves have been used as an adulterant with
foxglove leaves (11.1-50).
Russian comfrey, Symphytum uplandicum Nym. (formerly Symphytum
peregrinum), is the result of a cross between Symphytum officinale
and Symphytum asperum (prickly comfrey) and is a tall herb
growing up to two meters in height. Its lilfe zone is between
12 and 18 degrees centigrade, with an annual precipitation of
0.5 to 2 meters and a soil pH of 5.3 to 6.8 (4.1-31). The plant
likes a moist environment and is found growing wild along rivers.
Considered a hardy perennial, Russian comfrey can be grown in
colder northern temperate climates. Symphytum caucasicum
is a commercially available ornamental herb with blue flowers.
[Note: References listed above in parentheses can be found in
full in the original reference].
Last modified 6-Dec-1997