Common comfrey (Wallwort)

While the leaves of the common comfrey ( Symphytum officinale ) were once eaten in small quantities, today it is recommended that the plant is only used externally on intact skin. The reason for this is the potentially harmful alkaloids in the medicinal plant known as comfrey .

Use in the kitchen:

Can you eat comfrey? Comfrey, borage , viper's bugloss , coltsfoot, butterbur, lungwort and stone seeds have three things in common: they are traditional medicinal plants and former food plants, but they also contain liver-toxic alkaloids. Occasional consumption of small amounts was once considered harmless. Today, the Federal Institute for Risk Assessment ( BfR ) recommends avoiding the consumption of foods containing pyrrolizidine alkaloids.

Purchasing - where to buy?

Dried comfrey roots and comfrey leaves are available online. Not all sales websites point out the potentially harmful alkaloids and the fact that they are only for external use. Pharmacies and drugstores sell ointments, nutritional supplements, oils and other finished medicines containing comfrey extracts.

Ointments and gels containing comfrey can often be purchased in combination with other medicinal herbs such as St. John's wort, marigold, arnica, echinacea or peppermint . ¹

Is comfrey dangerous? Ask your pharmacist for comfrey products that come from pyrrolizidine-free or low-pyrrolizidine plant varieties and that have also been largely freed of these alkaloids using special processes. ^2,17

We have not yet found any comfrey products in supermarket chains such as Coop , Migros , Denner , Volg , Spar , Aldi , Lidl , Rewe , Edeka or Hofer as well as in the organic supermarkets Denns and Alnatura .

Found in the wild - Season:

Where can I find comfrey? Comfrey is an indicator plant for nitrogen-rich soils. The plant prefers a sunny to partially shaded location with moist, nutrient-rich (clay) soils. Comfrey can be found in ditches, on damp roadsides, on damp meadows, on banks, in alluvial forests, on moorland meadows, in fields and in bushes. ^3,4

The stems, which can grow up to 1 m tall and have lanceolate, rough-haired leaves, grow from a thick, juicy rootstock that is black on the outside and white on the inside. The bell-shaped, red-violet, sometimes yellowish-white flowers sit in overhanging clusters. ⁴

Season : The flowering herb, leaves and roots are harvested. Since the wound-healing ingredient allantoin is at its highest from January to March and decreases towards summer, the roots should be harvested in early spring or from October onwards. The rhizomes are dug up, freed from any adhering soil, cut lengthwise and hung on strings to dry. In spring, the shoots, young leaves, flowers and buds also contain allantoin. ^4.5

Storage:

Well-dried comfrey roots should be stored in glass jars or cardboard boxes lined with kitchen paper. Even a small amount of residual moisture can cause the roots to mold. Plastic or metal containers are not suitable for storing comfrey roots, as they break down the allantoin when they come into contact with metal. ⁵

Ingredients - nutritional value - calories:

The roots, leaves and herb of the common comfrey contain plenty of mucilage (fructans), up to 1.5% allantoin, 4-6% tannins, rosmarinic acid, choline, flavonoids, starch, triterpenes, vitamin B ₁₂ formed by microorganisms on the surfaces of the plant parts, other B vitamins , phytosterols and silicic acid. Depending on the growing area and variety, comfrey contains up to 0.6% pyrrolizidine (pyrrolizidine alkaloids). ^4,6,7

In March, the allantoin content in the root is 0.6-0.8% and decreases steadily throughout the year. ¹

Health aspects - effects:

What is comfrey good for? The main medicinal active ingredients of comfrey are allantoin and choline. Comfrey contains the highest naturally occurring levels of allantoin of any plant. ⁴ Chemically produced allantoin is now an important component of creams and medicines, eg for treating wounds or to loosen the skin for the penetration of active ingredients.

Allantoin dissolves wound secretions, liquefies pus and stimulates new tissue formation. The drainage of fluid from the wound surface promoted by allantoin also serves to flush out germs and bacterial toxins. ^4,6

Choline promotes blood circulation, particularly increased blood flow to injured tissue. The active ingredient reduces the leakage of tissue fluid and thus the formation of edema and allows hematomas (bruises) to disappear more quickly. ⁶

Dangers - Intolerances - Side effects:

Studies with isolated pyrrolizidine alkaloids from comfrey have shown a risk to fertility and damage to the fetus (reproductive toxicity) in animals. Further animal studies suggest that pyrrolizidine alkaloids are harmful to the liver (hepatotoxic) and carcinogenic when administered orally. It has been shown in pregnant animals that unborn animals suffered from liver damage after the mother had ingested pyrrolizidine alkaloids orally. In the laboratory, it has been shown that pyrrolizidine alkaloids have a genetic altering effect (genotoxic). ⁸

For humans, pyrrolizidine alkaloids are harmful to the liver and are considered mutagenic and carcinogenic. The liver forms highly toxic degradation products from the alkaloids. ²

Internal use in the form of tea, powder, capsules or consumption as a vegetable is no longer acceptable. When used externally on the skin, interactions are hardly known. Allergic reactions are rare. ^1,9,10 Contact with the eyes or mucous membranes should be avoided. ⁸

The Federal Institute for Drugs and Medical Devices ( BfArM ) stresses that comfrey applications may only be carried out on intact skin. Contraindications apply to pregnancy, breastfeeding and small children under three years of age, as no studies on safety are available. ^4,5,8,9 In general, use in children and adolescents under 18 years of age is not recommended. ⁸

To date, there are insufficient data on the absorption of pyrrolizidine alkaloids through the skin. The daily dose of pyrrolizidine alkaloids for adults should be less than 0.35 μg per day. ⁸

Due to their extreme toxicity, the Federal Institute for Risk Assessment ( BfR ) calls for zero tolerance for pyrrolizidine alkaloids in food. In the case of herbal medicines, the Committee on Herbal Medicinal Products ( HMPC ) has set limits for liver-toxic pyrrolizidines in products containing comfrey. ¹¹

There is no restriction on the duration of use for finished medicinal products containing comfrey extracts. ⁹ Homemade preparations containing comfrey should not be used on intact skin for more than 10 days and not for more than 4 to 6 weeks per year in total. The skin must not be broken or irritated. ^8,10

Use as a medicinal plant:

The Committee for Herbal Medicinal Products ( HMPC ) has classified comfrey as a traditional herbal medicinal product. Comfrey is to be used exclusively for the indicated indications for symptomatic relief. ⁸

Clinical studies confirm the following external applications on intact skin: painful muscle and joint complaints, bruises, strains, sprains (after the acute phase has subsided), back pain, knee joint arthrosis and local circulation improvement. ^9,10,12

The daily dose for adults is three to four applications per day for (homemade) ointments or other preparations (max. 35% root extract) ( European Scientific Cooperative on Phytotherapy / ESCOP ). The HMPC recommends applying a thin layer twice a day for semi-solid dosage forms (10% liquid extract). ^8,13

What can you do with comfrey? Comfrey root preparations can be made for external use in the form of wraps and poultices. To do this, boil 5-10 g of dried and coarsely powdered roots with 100 ml of water. After 15 minutes of soaking, you can pour off the remaining water. If you have a fresh root to hand, you can grate it coarsely and apply the pulpy mass to the affected area. Wrap the affected part of the body with a cotton cloth and allow the preparation to take effect for at least 30 minutes or overnight.

Alternatively, you can dry the root at a maximum of 40 °C and grind it into powder in an old coffee grinder. This can be used to make a paste all year round. The industry also produces a tincture with at least 50% alcohol. In naturopathy, a fat extract of the fresh comfrey root is made with lard. Allantoin undergoes catalytic decomposition if it comes into contact with metal for a long time.

Cosmetics use allantoin in skin creams, shower gels, sunscreens, aftershaves, toothpaste and products against excessive sweating (hyperhidrosis) and skin irritations. This soothes the skin and accelerates cell formation (building or regeneration). Although allantoin has no antiseptic properties, it supports the healing of wounds that are difficult to heal. Professionals use the larvae of the Lucilia sericata species of fly for wounds with necrotic tissue, as they specifically feed on necrotic tissue and release a lot of allantoin in the process (Römpp Online).

An infusion for wraps and poultices can also be prepared using fresh or dried flowers and leaves. Fresh plant juice can be preserved with alcohol. To make tinctures, a plant extract can be used with oil or alcohol.

Folk medicine - natural medicine:

In the past, comfrey was used on open wounds, for chronic suppurations, so-called leg ulcers and cell tissue inflammations. ⁴ Other indications were and are psoriasis, eczema, varicose veins, arthritis, hemorrhoids, breast inflammations, bone fractures, inflamed bunions or leg ulcers. ¹⁴

In traditional medicine, comfrey was and is also used for poorly healing fractures, sore muscles, tendon, tendon sheath and bursitis, bleeding and irritation, nail bed inflammation, boils, thrombophlebitis (acute thrombosis and inflammation of veins), swollen lymph nodes due to feverish infection and for inflammatory-rheumatic joint diseases. ^7,14

Until not so long ago, comfrey was an important medicinal plant ingredient in natural and preventative cuisine. The very young leaves were eaten in small doses. It was assumed that occasional consumption of small amounts was harmless. ⁷

Comfrey leaves were used as a food plant in folk medicine (herbal tea), in the form of "comfrey vegetables" (from the English term comfrey) or raw salad. ⁶ In central Switzerland, the leaves were baked in dough or used to wrap food. ³

Please note that internal use is no longer recommended (see above).

Occurrence - Origin:

Comfrey is widespread throughout Europe from the Mediterranean to the Caucasus. It is quite common in Central Europe, mostly naturalized in Northern Europe and rather rare in Southern Europe. The eastern extent of the comfrey (comfrey) reaches as far as western Siberia and China. ^3,4,14

Cultivation in the garden or as a pot plant:

Comfrey is a perennial semi-rosette plant with a lifespan of around 20 years. The roots reach up to 1.8 m deep. Comfrey reproduces by branching the turnip-shaped rhizome and by cutting off parts. The undemanding and fast-growing plant sprouts every year, even under adverse conditions. Comfrey grows particularly well on nitrogen-rich (e.g. fertilized or mulched) soils. ³

If you want to remove comfrey from your garden, you should dig up as much of the roots as possible (at least 50 cm). To prevent the plant from spreading like a weed, you can cut off the flowers or the entire plant before the seeds ripen. ³

Common comfrey contains plenty of nitrogen (C/N ratio = 10:1) and has a high potassium content in all parts of the plant. Thanks to these properties, the plant is suitable as mulch material or for making plant manure. ³

To ensure that bumblebees and other insects can benefit from the flowers, the plant should only be cut back after flowering. ³

Other borage plants such as ox tongue, borage, viper's bugloss and dog's tongue are good companions in the garden. ¹

Cultivation - Harvest:

Today, almost pyrrolizidine alkaloid-free hybrids ( Symphytum x uplandicum ) from Symphytum officinale and Symphytum asperum are used to produce medicines and ointments based on fresh plant extracts (Traumaplant®, Kytta®). The desired ingredients such as allantoin, choline or rosmarinic acid are still contained. This type of comfrey has been protected since 2008. This variety is mainly cultivated in southern Germany. ¹⁵

Danger of confusion:

Sprouting leaves of the common comfrey can be confused with the poisonous foxglove ( Digitalis ssp.). The different leaf properties serve as a distinguishing feature. The leaves of the foxglove are serrated and feel velvety soft. The rough and bristly comfrey leaves, on the other hand, can be recognized by their smooth edges. ⁵

Animal protection - species protection - animal welfare:

The main pollinators of the bell-shaped comfrey flowers with their narrow corolla tube entrances blocked by pharyngeal scales are long-nosed honey bees, larger wild bees and bumblebees. Short-nosed earth bumblebees gain access by biting the side of the corollas. ¹⁶ According to Wikipedia , spontaneous self-pollination also seems to be possible. ³

Common comfrey serves as food for bees mainly during the months of May to September (summer nectar). Nectar is the general term for the food that the bees bring in, i.e. nectar, pollen and honeydew. The nectar value of comfrey is medium and the pollen value low (nectar value and pollen value scale: none, low, medium, high, very high). The two values reflect the benefit for insects and serve as guidelines and decision-making aids for bee and insect-friendly new plantings and gardening. ¹⁶

General information:

Common comfrey ⁽ Symphytum officinale ) belongs to the genus Symphytum within the family Boraginaceae.3 Borage ( Borago officinalis ) and the genus Echium also belong to the same family .

The name of this medicinal plant, which has been known since ancient times, indicates its medicinal use. In the past, bones were generally referred to as "legs". "Well" comes from the Old German verb "wallen" and refers to the "growing together or healing" of bones or wounds. ⁹ The Latin term consolida ( maior ) ( consolidare = to fasten, to grow together) is a loan translation of the Greek symphyestai . ³

Alternative names:

Other names for the true comfrey include common comfrey, common comfrey, medicinal comfrey, comfrey, bee herb, hare's leaf, milkwort, comfrey root, scallion root, black root, comfrey, comfrey or wound healing. The alternative name comfrey is also known. The true black salsify ( Scorzonera hispanica ) is a different plant. It also contains allantoin, as do wheat germs, soy germs, rice, cauliflower, green beans and horse chestnut shells.

In English, comfrey is known as comfrey, comphrey, boneset, consound, knitbone, common comfrey, cultivated comfrey, Quaker comfrey or slippery-root.

Keywords for use:

In parts of Austria, older parts of the plant were mixed with tobacco. ³ In agriculture, comfrey is used as a nitrogen-rich fertilizer and as a fodder plant. ¹⁴

Literature - Sources: