Comfrey is a perennial plant native to most of North
America, Europe, and western Siberia. It is found in moist, watery places. The
rootstock is fleshy, branched, and white internally. The plant produces an
angular hairy stem which grows up to three feet in height, branching only near
the top. It bears large, oblong, lanceolate leaves, which are green, rough, and
covered with short hairs. Basal leaves are also present, usually lying along
the ground. Whitish, pale purple flowers grow in racemes from the upper leaf
axils, blooming from May to August. The fruit consists of four small nuts
located at the bottom of the calyx.
Other common names for this plant are:
|| Gum Plant
|| Slippery Root
| Healing Herb
|| Amino Acids
| Vitamin A
|| B Complex
|| Vitamin C
| Vitamin E
PROPERTIES AND USES
Anodyne - a substance which relieves pain, usually
with accompanied sedation.
Astringent - an agent which causes the constriction
or contraction of tissue.
Demulcent - an agent which smooths the mucous
membranes on contact.
Diuretic - Diuretics form a class of drugs which
increase the volume of urine produced by the kidneys. It can be used
effectively to treat mild cases of edema when kidney function is good and when
the underlying abnormality of cardiac function, capillary pressure, or salt
retention is being corrected simultaneously. Diuretics are not an appropriate
treatment for edema caused by inflammation of the kidneys, and are useless in
cardiac edema associated with advanced kidney insufficiency.
Emollient - a skin dressing or soothing
Expectorant - an agent which stimulates the outflow
of mucus from the lungs an bronchials.
Hemostatic - any drug, medicine, or blood component
that serves to stop bleeding.
Refrigerant - an agent which alleviates heat,
fever, or thirst.
Vulnerary - any form of first aid for wounds and
Comfrey is one of the most valuable herbs known to botanic
medicine because it has beneficial effects on all parts of the body, and can be
used as an overall tonic. It has been successfully used for centuries as a
wound-healer and bone-knitter, strengthening the skeleton and the pituitary
gland. Comfrey helps in the calcium-phosphorus balance by promoting strong
bones and healthy skin. It helps promote the secretion of pepsin and is a
general aid to digestion. It is one of the finest healers for the respiratory
system, and can be used internally and externally. Comfrey has been used with
great success to check hemorrhage from the stomach, lungs, bowels, kidneys, and
Comfrey root works longer in the intestines than does
pepsin. Comfrey root's mucilage helps heal ulcers by coating them and
destroying amoebic parasites.
Laboratory studies done in India have shown that the
mucilage in herbs like comfrey root act as a strong deterrent to Escherichia
coli and similar intestinal microorganisms by absorbing them and other
According to British scientific studies, comfrey has seven
times more protein than does soybeans and eight times more carbohydrates.
Comfrey root is extremely mucilaginous; it has more mucilage than does
marshmallow root. Comfrey root has between 0.6-0.8% allantoin and a large
percentage of natural plant gum. Comfrey root's mucilaginous properties work on
the lungs in the same manner as in the colon.
Comfrey contains two alkaloids which, when taken in
sufficient quantities, have produced depression in the central nervous system.
Comfrey may be contraindicated in patients on dietary potassium restrictions.
Considerable amounts of allantoin are present in the root and leaves, but it is
virtually nontoxic. At least eight pyrrolizidine alkaloids have been identified
in the leaves of Russian comfrey (S. uplandicum): echimidine, symphytine,
locopsamine, intermedine, acteylcopsamine, acetylintermedine, symlandine, and
angelyl 9 echimidinylretronecine. Some, but not all pyrrolizidine alkaloids
cause liver damage. Several reports of pyrrolizidine alkaloid poisonings in
humans cited both liver and lung damage.
In another study conducted with several groups of inbred
strain ACI rats of both sexes, the incidence of liver tumors was higher in
those groups fed a diet containing comfrey root than in those fed a diet
containing comfrey leaf, even though the percentage of comfrey flour is higher
in the leaf diet than in the root diet. Furthermore, rats became seriously
affected when roots were fed in a concentration of 4% in two groups of rats,
whereas rats tolerated the feeding of the leaves. However, rats in one groups
could ingest an 8% diet of roots without more serious toxic effects compared
with those in another group given only a 4% diet. This suggests that comfrey
toxicity can be varied, even though plant material was collected in the same
area and at the same time.
Poisoning can result when foxglove or digitalis is
mistaken for comfrey and inadvertently consumed. Symptoms were weakness,
nausea, envisioning yellow halos around objects, and poisoning, sometimes
resulting in death.
Recently the Australian government banned the sale and use
of comfrey in herbal medications due to a fear of toxic factors.
DRUG PRECAUTIONS AND INTERACTIONS
Any of the following drugs may be imperfectly absorbed if
comfrey is being used on a daily basis: tetra- cycline derivatives, oral
anticholinergics, phenothiazines, digoxin, isoniazid, phenytoin, and warfarin.
The urinary excretion of alkaline drugs, such as
amphetamines or quinidine, may be inhibited by the antacid nature of comfrey.
The antacid nature of comfrey may also decrease or delay the absorption of
nalidixic acid and the sulfonamides.
The antituberculous activity of comfrey may potentiate the
adverse effect of other antituberculous drugs, especially ethionamide.
The anti-inflammatory activity of comfrey can be seriously
inhibited by phenobarbital and certain other sedatives and hypnotics, such as
chloral hydrate and meprobramate. This is also true of beta-adrenergic blocking
agents, such as propranolol.
The topical application of the astringent herb comfrey, in
conjunction with the acne product tretinoin (retinoic acid, vitamin A acid),
may adversely affect the skin.
The antacid properties of comfrey may enhance the renal
tubular resorption of the antiarrhythmic drug quinidine, leading to increased
quinidine serum levels.
To the extent that comfrey's action depends on the
presence of cholinergic substances, its action will be affected by the decrease
in cholinergic-receptor stimulation produced by anticholinergics.