Comfrey – characteristics, cultivation, use and curative effects


Comfrey (Symphytum officinale) is one of the oldest known medicinal plants, which is mainly used for joint pain, muscle problems or sprains. The roots of comfrey contain active ingredients that allow rapid detumescing and rapid pain relief. In the past, its leaves were a valued culinary ingredient in the kitchen. Due to the contained pyrrolizidine it is recommended to consume only small amounts of the herb.

Profile of comfrey:

Scientific name: Symphytum officinale

Plant family: borages

Other names: symphytum, boneset, consound, knitbone,slippery-root

Sowing time / Planting time: February – May

Flowering period: May – October

Harvest time: April – October

Location: sunny to partially shaded

Soil quality: nutrient-rich and loose soils

Use as a medicinal herb: wound healing, bruising, muscle pain, joint pain, arthrosis, rheumatism

Use as aromatic herb: not recommended internally

Plant characteristics and classification of comfrey

Origin and distribution of the Comfrey

The native home of the comfrey is suspected today in Asia Minor. From there, the plant spread to Western Siberia. Due to the increasing prominence as a medicinal plant, the plant also known as boneset was increasingly adventived to Europe. In the Middle Ages, some monasteries grew comfrey, which made it very fast to find throughout Europe.

In Northern and Western Europe, comfrey can be found in nutrient-rich and humid locations. Well-known localities are field edges and roadsides, nutrient-rich meadows and waysides, as well as on the waterfront of ponds and lakes.

Systematics of Symphytum officinale

The common comfrey (Symphytum officinale) is a species of the borage family (Boraginaceae). It is thus directly related to the borage, often referred to as cucumber herb, or the viper’s bugloss commonly found on wild meadows. The genus comfrey (Symphytum) includes more than 50 species, most of which are native to Western Asia and Western Europe. In addition to the common comfrey, the creeping comfrey and the rough comfrey still are known.

The comfrey that occurs naturally in Western Europe differs once more into three subspecies (varieties):

  • common comfrey (Symphytum officinale subsp. officinale)
  • Marsh tuber (Symphytum officinale subsp. Uliginosum)
  • White comfrey (Symphytum officinale subsp. Bohemicum)

For completeness, the blue comfrey (Symphytum x uplandicum) is to be mentioned, which is a hybrid of common comfrey and the rough comfrey (Sympyhtum asperus).

comfrey flower
comfrey flower

Features of the comfrey

The common comfrey is a typical herbaceous and perennial plant, which usually reaches stature heights of around 60 cm (24 inches), but can also grow up to 110 cm (43 inches) in optimal site conditions. With its up to 50 cm long (20 inches) roots, it is usually anchored deep in the ground. The rootstock is usually roughly branched and brownish to black. At the main root sit many fine, partly whitish secondary roots or root hairs.

The leaves are usually colored mint green and show a lanceolated or pointed form. The leaf margins are slightly wavy. The surface of the leaves shows a honeycomb pattern and very noticeable leaf-veins. Both the leaves and the light green stems are covered with numerous glandular hairs that give the plant a bristly look and feel. Basically, the sheet size decreases significantly from bottom to top.

During flowering, which is usually to be expected between the end of May and the beginning of October, the plant forms grape-like inflorescences, which are referred to here as helicoid cyme. The flowers are always hermaphroditic and usually purple to pink in color. Rarely yellowish flowers can be found. Usually the flowers are between 1.2 and 1.7 cm (0.5 and 0.7 inches) long and always inclined towards the ground. Each flower has five stamens.

At the time of the fruit ripening, which usually begins at the beginning of October, the schizocarps, which are typical of the borages, develop from the flowers. schizocarp fruits are characterized by the fact that during ripening fall apart in several fruit parts (schizocarp). Every single hermaphrodite is up to 5 mm (0.02 inches) long and strikingly black.

Comfrey cultivation and care

Comfrey is one of the more easy-care plants. However, if the plant finds an optimal location, it can also be a nuisance, as it spreads quite quickly and is deeply rooted. When planting, therefore, a separate area should be chosen, from which the plant can be easily removed if necessary. However, since it is also a good crop and can be used for both health and some garden applications such as comfrey dung water, the perennials are sometimes found in some garden beds.


It is possible to grow comfrey in both sunny and partially shaded spots. However, full sun should be avoided, because especially on hot days, the plant quickly suffers from lack of water. Soils should be able to hold moisture, be nutrient-rich and loose.


The dark brown to black seeds of the comfrey can be put into the open garden bed from the end of February until the beginning of May. In principle, the seeds need light to germ, the grains also grow if put to a sowing depth of 1 cm (0.4 inches). Nevertheless, when cultivating several plants, a planting distance of about 50 to 60 cm (20 to 24 inches) to the next plant should be kept, otherwise the roots will live in direct competition for nutrients. The germination of the seed usually begins only when when the frosty days are over. A germination period of 14 to 21 days is not uncommon.


Comfrey is one of the moderate feeder and therefore has a higher nutrient requirement than many other herbs. If the plant grows in a good nutrient-rich garden soil, it does not necessarily need to be fertilized. However, for potted crops or in gardens with more nutrient-poor soils, a nitrogen-based fertilizer should be used. In open ground, if available, good compost or manure are sufficient. If it grows in pots or tubs, liquid organic fertilizers are usually better. Here it is usually necessary to fertilize at intervals of six to eight weeks.


Through the taproots that comfrey develops during time, steady watering is usually not required. The exceptions are young plants that do not grow sufficiently long roots and longer lasting hot days without rainfall. The comfrey indicates, however, by limp hanging leaves quite early, when it needs water.

Diseases and pests

Comfrey is considered a robust plant. With increasing age in the course of the season, holes are sometimes formed in the leaves, which are usually caused by flea beetle. In most cases, this is not nice to look at, but not particularly dangerous for the plant. In unfavorable cultivation and site conditions and in rare cases by bad climatic conditions (many wet cold days during the summer days) comfrey tends form gray mold. Then, it is advisable to quickly remove affected leaves.


If the plants grow too thick or too big, the plants should be trimmed. As in bad weather conditions too much moisture can accumulate between dead leaves, which boosts the formation of gray mold.


The common comfrey is a native plant and thus well adapted to our climate. Wintering measures are therefore not required.

Use of comfrey

In the past, comfrey was used both as a kitchen plant and as a medicinal herb. Due to the pyrrolizidine alkaloids contained, however, comfrey leaves are barely eaten today. It therefore only matters as a medicinal plant a role.

In the kitchen

Comfrey is still occasionally on the menu for wildflower enthusiasts. The leaves of the comfrey, like borage, can be used as a mild vegetable in salads. Browned in butter comfrey truly makes a good figure. Occasionally there are even recipes for hearty and sweet pancakes made with chopped comfrey leaves.

The leaves contain significant vital substances such as vitamins or silicic acid and are also eatable in small quantities. However, it is recommended to use comfrey rarely and only in small amounts. The entire plant is often high in pyrrolizidine alkaloids, which are most likely to cause liver toxicity. Small amounts are usually not a problem for healthy people.

As a medicinal herb

Comfrey is one of the most important medicinal plants today. Especially for muscle or joint complaints, its roots are a natural alternative to synthetic drugs.

The use of comfrey has been known since ancient times. Already in ancient Rome, the healing power of the plant must have been known. Glaucus, one of the doctors of the famous Egyptian queen Cleopatra, used a comfrey root porridge to prevent bruising, fractures or sprains. The Greek physician and pharmacologist Dioscorides had written several pages about comfrey in his book of remedies De materia medica. Of course, comfrey was also not missing at other healers of the Middle Ages such as Hildegard von Bingen or Paracelsus.

In the herbal book by P. A. Matthioli, comfrey was applied both internally and externally. The herb, then called Walwurtz (boneset), was used for lung inflammation (purulent lungs), bloody sputum, and red dysentery (usually synonymous with diseases that cause bloody stools/fecals). Externally, it was one of the most popular medicinal plants. It has been used to quicken wound healing on open wounds, helped relieve body aches and even been used in venereal diseases/STDs (including gonorrhea). Above all, the root and the leaves were used. Of the leaves one made frequently so-called comfrey-patches, which were wound around the wound. Today, comfrey applications on open wounds are no longer recommended.

In today’s natural medicine for many external complaints comfrey is not possible to imagine one without the other. The roots, and in smaller quantities also the leaves, contain medically active ingredients such as allantoin, choline, mucilage and tannins (including rosmarinic acid).

These substances can have the following healing effects on the human organism:

  • anti-inflammatory
  • stimulating the blood flow
  • analgesic
  • reduces swelling (decongestant)
  • antibacterial
  • wound-healing

These healing effects are today among others useful for the following diseases and conditions:

  • osteomyelitis
  • wound healing
  • bone fractures
  • contortions and sprains
  • strains
  • bruises
  • arthrosis
  • Joint and limb pain

If comfrey root and leaves were previously used, today only the root (Symphyti radix) is used. Due to the containing pyrrolizidine alkaloid, which probably cause liver toxicity, comfrey should no longer be taken internally in the form of teas. Therefore, wraps and compresses as well as self-prepared or bought ointments are common.

In addition to compresses, comfrey ointments can quickly relieve joint pain or annoying neck tension. It is an excellent herb for the bones and joints. Above all, people who have to do heavy physical work or standing and sitting a lot, can gently rub the affected areas with a comfrey ointment and experience rapid relief. Good products provide significant pain relief after just two to three hours.

It is also used in homeopathy, especially for badly healing wounds, blunt facial injuries, torn ligaments, phlebitis, or concomitant treatment of bone tumors. Usual dosage amounts are the potencies D1 to D30, which are available in the form of globules or pills.

Side effects

Do not take comfrey internally as it may contain hepatically toxic pyrrolizidine alkaloids. When used externally in the form of compresses or ointments, chronic skin diseases should be excluded. Comfrey must not be used on open wounds. For existing skin diseases treatment should be discussed with a doctor or pharmacist.

comfrey blossom
comfrey blossom

Preparation of a comfrey envelope

  • Mincing or chopping the roots
  • Cooking a comfrey extract (50 to 100 grams (1.7 to 3.0 oz), 10 minutes cooking time)
  • Sieve and leave to cool
  • Dip mull in brew

For a comfrey wrap an extract is first made so that the active ingredients are extracted from the comfrey root. For this purpose, cook about 50 to 100 grams (1.7 to 3.0 oz) of cut roots for about 10 minutes and remove them.

The hot extract should then cool slightly until it is lukewarm. Then you put a mull in the container and put the wrap on the affected area. Please make sure that the wound is not open, as in the worst case, contamination can lead to blood poisoning.

If painful complaints such as abrasions, bruises and sprains are treated, yiu can add amber [Hypericum perforatum] and common marigold [Calendula officinalis]. Amber also have an anti-inflammatory effect. Marigold, on the other hand, has an anti-edematous effect and can thus alleviate swelling.

Comfrey as a plant strengthening agents

Comfrey is not only an enrichment as a medicinal herb, but also strengthening for plants. In fact, gardeners who try their garden without insecticides use comfrey extracts to make weakened or pest-prone plants more resistant to old-school pests such as aphids, spider mites or fungi.

It can be applied differently:

  • Hot extract: preparation like tea
  • Comfrey swill/dung water: a comfrey extract is allowed to ferment for about 14 days
  • Macerate (cold water extract): Comfrey is mixed with water and allowed to stand for about a day

One of the most common uses is spraying with comfrey dung water. The foliage of the plant is collected, crushed and placed in a container. The container should, depending on need and garden size, take about 5 to 10 liters (1.3 to 2.6 gallons (us)). The container is then filled up with water and covered with a cloth or a fine mesh. After about 9 to 14 days, the gung water is ready. At least once a day, the broth should be stirred up well. If the smell is too obtrusive, it can be significantly reduced with some rock flour or zeolite flour. The swill is then initiated into the soil diluted with water (ratio about 1:10). The plants themselves become more resistant in the long term and even get some nutrients (mainly nitrogen and minerals).

Comfrey extracts, whether as a hot extract or macerate, are usually used when plants are acutely attacked by pests or diseases. The preparation is applied either directly or with a 1: 2 dilution to the plants. The procedure should be repeated daily for about a week. It is important that the comfrey extracts have not already fermented, as this can otherwise damage the leaves and plants.

Buy – What is there to pay attention?

Comfrey as a classic medicinal plant is used by many people who suffer from musculoskeletal disorders. Occasionally comfrey is also used as an ornamental plant in the garden or on the balcony, which is why the plant is sometimes offered in garden centers and plant markets.

For fresh plants, one should especially observe the underside of the leaves, where aphids can occasionally be found. In addition, there should be no yellowish discoloration on the leaf margins, as this may indicate an acute lack of nutrients or root damage.

Gardeners, who cultivate their garden ecologically or sustainably, often like to fall back on comfrey swill or dung water. For this purpose, there are already crushed and pulverized products to purchase, which can be used to produce plant strengthening agents in no time at all. In general, comfrey swill or dung water actually provide good added value in gardens that are often infested with pests or diseases. For very abundant infestation of various pests but no miracle may be expected, since the comfrey extracts primarily strengthens the resistance of other plants.

Anyone with joint complaints such as pain, sprains or arthrosis may find comfrey to be a beneficial and gentle remedy. If the effort is too great to produce compresses, wraps or ointments, you can already buy finished products from numerous well-known suppliers. These ointments ensure that the painful or swollen areas cool down a bit and provide gentle relief. The ointments are at about 9 to 15 EUR/$. Although at first glance quite expensive. However, they can be used sparingly and last quite a long time.

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