Comfrey (comfrey), raw (organic?)

While the leaves of the common comfrey ( Symphytum officinale) were once eaten raw 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. Organic ?

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. ¹

Purchasing - Storage

We have not yet found any comfrey products in supermarket chains such as Coop, Migros, Denner, Volg, Spar, Aldi, Lidl, Rewe, Edeka, Hofer or Billa, or in the organic supermarkets Denn's Biomarkt and Alnatura. Fresh comfrey can only be collected in the wild.

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 bought in combination with other medicinal herbs such as St. John's wort, marigold, arnica, echinacea or peppermint. ²

Is real 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. ^3,4

Found in the wild

Where can I find comfrey? 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. ⁵

What does real comfrey look like? How can I recognize comfrey? The stems, which are up to 1 m high and have lanceolate, rough, hairy 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. ⁵

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. ^5,6

Storage tips

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. ⁶

Ingredients - Nutritional values - 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 B₁₂ 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). ^5,7,8

In March, the allantoin content in comfrey root is 0.6-0.8% and decreases steadily throughout the year. ²

You can find all the ingredients of comfrey, the coverage of the daily requirement and comparison values with other ingredients in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.

Health effects

The entire comfrey is rich in various phytochemicals and contains, in addition to polysaccharides and fatty acids, about 31% phenolic acids, 23% pyrrolizidine alkaloids and 18% flavonoids. In recent years, numerous in vitro and in vivo studies have investigated the health potential of comfrey extracts. These show health-promoting properties, such as anti-inflammatory, wound-healing and pain-relieving effects. ¹⁰

Secondary plant substances

Many of the health benefits of externally applied comfrey can be attributed to the secondary plant substances it contains. Our article on secondary plant substances provides an overview of the classification of substance groups, their occurrence in food and possible effects on humans. Comfrey contains the following secondary plant substances, among others: ^9,10

• Isoprenoids: Triterpenes: Saponins, Phytosterols; Iridoids
• Alkaloids: Pyrrolizidine alkaloids (including intermedin, lasioscarpine, myoscorpine, symlandine, symphytin)
• Polyphenols: Phenolic acids: hydroxybenzoic acids (dihydroxybenzoic acid, p-hydroxybenzoic acid, salicylic acid, vanillic acid), hydroxycinnamic acids (chlorogenic acid, caffeic acid, rosmarinic acid, cinnamic acid, p-coumaric acid, ferulic acid, danshensu, sageric acid, sinapic acid, salvianolic acid); flavonoids: flavonols (quercetin, quercetin derivatives, kaempferol, isorhamnetin, myricetin), flavanols (catechin, epicatechin), flavones (apigenin, luteolin), flavanones (naringenin, pinobanksin); lignans (globoidnan A and B, rabdosiin); tannins (ellagic acid)
• Other nitrogen-containing compounds: ureide (allantoin), amines (choline)
• Other organic compounds: quinones; glycosides (roseosides); furanocoumarins (umbelliferone); dicarboxylic acids (malaxic acid); hydroxycarboxylic acids (citric acid, malic acid, gluconic acid); carboxylic acids (sarracinic acid, trachelic acid, viridifloric acid); aldehydes; phenylethanoids

However, it should be noted that the composition of secondary plant substances in comfrey can vary depending on the variety, time of harvest and growing conditions. Therefore, quantities are only of limited use and should only be understood roughly.

Comfrey defends itself against external influences with pyrrolizidine alkaloids (PA). They are found primarily in the roots (30 to 500 mg/100g), less in the leaves (11 to 24 mg/100g) and minimally in the flowers of the plant. In view of the toxicological concerns, researchers have developed numerous methods to remove them. ¹⁰

What is comfrey good for? The main medicinal ingredients in comfrey are allantoin, choline and the phenolic compounds. Choline is an amine and a fundamental component of lecithin. Comfrey contains the highest naturally occurring levels of allantoin among plants. ⁵ Allantoin is produced by the breakdown of uric acid and is found primarily in the root. Allantoin dissolves wound secretions, liquefies pus and stimulates the formation of new tissue. The drainage of fluid from the wound surface, which is promoted by allantoin, also serves to flush out germs and bacterial toxins. ^5,7 Choline promotes blood circulation, particularly increased blood flow to the 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. ⁷

Comfrey is an important ingredient in creams and ointments, e.g. for joint problems, tendonitis, gout or bone fractures. ⁸ Studies show the potential of homeopathic pastes made from comfrey root mother tincture for the development of new osteogenic agents for bone mineralization and healing. ¹⁰

Extracts from the leaves of comfrey have anti-cancer effects on various human cancer cell lines. Extracts from the flowers show cytotoxic effects on breast cancer cells. ¹⁰

Medical studies have observed the potential of the phenolic components of comfrey as a complementary therapy for type 2 diabetes mellitus patients. ⁹ Other studies attribute antimicrobial and antioxidant effects to the phenolic components of comfrey root extracts. The prior removal of PA did not have a negative effect on these effects. S. officinale extracts have also been used to synthesize silver nanoparticles that protect UVB-stressed skin cells from collagen degradation and support the production of skin collagens. Given the advances in extraction and purification methods to protect against PA, future research will focus on other medicinal effects of comfrey. ¹⁰

Dangers - Intolerances - Side effects

Is comfrey carcinogenic? 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 liver-damaging (hepatotoxic) and carcinogenic when administered orally. In pregnant animals, it was shown that unborn creatures suffered from liver damage after the mother had ingested pyrrolizidine alkaloids orally. In the laboratory, it was shown that pyrrolizidine alkaloids have a genetic altering effect (genotoxic). ¹¹

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. ³

Internal use in the form of tea, powder, capsules or consumption as a vegetable is no longer acceptable. When applied externally to the skin, hardly any interactions are known. ¹¹ Allergic reactions are rare. ^2,12 Contact with the eyes or mucous membranes should be avoided. ¹¹

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. ^5,6,11,12 In general, use in children and adolescents under 18 years of age is not recommended. ¹¹

To date, there is insufficient data on the absorption of pyrrolizidine alkaloids through the skin. The daily dose of pyrrolizidine alkaloids for adults should be less than 1 μg per day. ¹¹

Due to their extreme toxicity, the Federal Institute for Risk Assessment ( BfR) calls for zero tolerance for pyrrolizidine alkaloids in food. ¹ In the case of herbal medicinal products, the Committee on Herbal Medicinal Products ( HMPC) has set limit values for liver-toxic pyrrolizidines in products containing comfrey. ¹³

There is no restriction on the duration of use for finished medicinal products containing comfrey extracts. ¹² 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. ^11,14 The skin must not be broken or irritated. ¹¹

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. ⁶

Is there a risk of confusion with borage? Confusion with borage or viper's bugloss is rare and is less dangerous to health. ²¹

Use as a recognised medicinal plant

The Committee for Herbal Medicinal Products ( HMPC) has classified comfrey as a traditional herbal medicinal product. ¹² Comfrey is to be used exclusively for the indicated indications for symptomatic relief. ¹¹

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. ^12,14

The HMPC recommends applying a thin layer twice daily for semi-solid dosage forms (10% liquid extract). ¹¹

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 100 g of comfrey root in 1 liter of water and strain it after 10 minutes. The resulting liquid can be used to make warm wraps. ⁵

Folk medicine - natural healing

In the past, comfrey was used on open wounds, for chronic suppurations, so-called leg ulcers and cell tissue inflammations. ⁵ Other indications were and are psoriasis, eczema, varicose veins, arthritis, hemorrhoids, breast inflammations, bone fractures, inflamed bunions or leg ulcers. ¹⁵

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 infections and for inflammatory-rheumatic joint diseases. ^8,15

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. ⁸

As a food plant, comfrey leaves were used in folk medicine (herbal tea), in the form of "comfrey vegetables" (from the English term comfrey) or raw salad. ⁷

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

Ecological footprint - animal welfare

The _CO2 footprint is the primary way to assess the climate friendliness of a food. This depends on various factors. The type of agricultural production (conventional vs. organic), seasonal, regional or domestic production or import by truck, ship or plane, different types of packaging and whether the goods are fresh or frozen all play a decisive role. ¹⁶ Since fresh comfrey is only found in the wild and is not used as a food due to its ingredients, we cannot provide any information on the _CO2 footprint or water footprint at this point.

For detailed explanations of various sustainability indicators (such as ecological footprint, _CO2 footprint, water footprint), see our article: What does the ecological footprint mean?

Animal protection - species protection

The main pollinators of the bell-shaped comfrey flowers with their narrow corolla tube entrances blocked by pharyngeal scales are long-tongued honey bees, larger wild bees and bumblebees. Short-tongued earth bumblebees gain access by biting the side of the corollas. ¹⁷

Common comfrey is mainly used as food for bees 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. ¹⁷

Worldwide occurrence - cultivation

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. ^5.15

Cultivation - Harvest

To grow in your own garden, sow comfrey seeds in March on a warm windowsill in nutrient-rich potting soil. In May, you can plant the young plants in their actual location in your own garden. A partially shaded to sunny spot with moist, humus-rich soil is ideal. Comfrey is an adaptable and undemanding plant. However, make sure it is watered sufficiently in the first year and fertilize the perennial plant occasionally. ¹⁸ Note that Symphytum officinale grows quickly and its long taproot makes it difficult to transplant. ¹⁹

Common 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. ¹⁸ You can harvest fresh leaves all year round. If you want to dry the leaves, harvest them shortly before flowering. The roots are best dug up in autumn and used fresh or dried before further processing. ¹⁹

Comfrey contains plenty of nitrogen, phosphorus, potassium, as well as numerous micronutrients and silica. Thanks to these properties, the plant is also suitable for making plant manure. ¹⁸

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

Other borage plants such as ox tongue, borage, viper's bugloss and dog's tongue are good companions in the garden. ²

Further information

Common comfrey ( Symphytum officinale) belongs to the genus comfrey ( Symphytum) within the borage family (Boraginaceae). The same family also includes borage ( Borago officinalis) and the genus Echium .

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. ¹²

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. 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 grown in southern Germany. ²⁰

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 the shell of the horse chestnut.

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

Other uses

Dried leaves were also used to make a smoking tobacco mixture. ⁸ In agriculture, comfrey is used as a nitrogen-rich fertilizer and as a fodder plant. ¹⁵