Symphytum officinale-Comfrey

Family: Boraginaceae

Other Names: Knitbone, Knit Bone, Ass Ear, Blackwort, Bruisewort, Knitback, Miracle Herb, Boneset, Gum Plant, Slippery Root, Wallwort

hazardsmallComfrey contains small quantities of a toxic alkaloid which can have a cumulative effect upon the liver. Largest concentrations are found in the roots, leaves contain higher quantities of the alkaloid as they grow older and young leaves contain almost none. Most people would have to consume very large quantities of the plant in order to do any harm, though anyone with liver problems should obviously be more cautious. In general, the health-promoting properties of the plant probably far outweigh any possible disbenefits, especially if only the younger leaves are used. Use topically on unbroken skin. May cause loss of appetite, abdominal pain, vomiting. Do not use with Eucalyptus. Do not combine with herbs containing pyrrolizidine alkaloids (e.g. agrimony, alpine ragwort, kelp, tansy ragwort).

Habitat: This is a common UK plant Comfrey grows in damp, often shady localities, in meadows, woods etc, especially near streams and rivers.

Description of Comfrey:

Symphytum officinale is a PERENNIAL growing to 1.2 m (4ft) by 0.6 m (2ft in) at a fast rate.
It is hardy to zone 5 and is not frost tender. It is in flower from May to June, and the seeds ripen from Jun to July. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Bees.

Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and can grow in heavy clay soil. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.


Comfrey tolerates most soils and situations but prefers a moist soil and some shade. Grows well in heavy clay soils. Best grown in an open sunny site in a deep rich soil if it is being grown for compost material. Plants can be invasive, often spreading freely by means of self-sown seed. The root system is very deep and difficult to eradicate, even small fragments of root left in the soil can produce new plants.


Seed – sow spring or autumn in a cold frame. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. If you have sufficient seed you can try an outdoor sowing in situ in the spring. Division succeeds at almost any time of the year. Simply use a spade to chop off the top 7cm of root just below the soil level. The original root will regrow and you will have a number of root tops, each of which will make a new plant. These can either be potted up or planted out straight into their permanent positions.

Collection: The roots should be unearthed in the spring or autumn when the allantoin levels are the highest. Split the roots down the middle and dry in moderate temperatures of about 40-60 degrees C.

Culinary uses of Comfrey:

Edible Parts: Leaves.
Edible Uses: Gum;  Tea.

Young leaves – cooked or raw. The leaf is hairy and the texture is mucilaginous. It may be full of minerals but it is not pleasant eating for most tastes. It can be chopped up finely and added to salads, in this way the hairiness is not so obvious. Young shoots can be used as an asparagus substitute. The blanched stalks are used. Older leaves can be dried and used as a tea. The peeled roots are cut up and added to soups. A tea is made from the dried leaves and roots. The roasted roots are used with dandelion and chicory roots for making coffee.

Symphytum_Officinale_botanicalMedicinal uses of Comfrey:

Actions: Vulnerary, demulcent, anti-inflammatory, astringent, expectorant.

Part Used: Root and rhizome, leaf.


The impressive wound-healing: vulnerary properties of Comfrey are partially due to the presence of allantoin. This chemical stimulates cell proliferation and so augments wound-healing both inside and out. The addition of much demulcent mucilage makes Comfrey a powerful healing agent in gastric and duodenal ulcers, hiatus hernia and ulcerative colitis. Its astringency will help haemorrhages wherever they occur. It has been used with benefit in cases of bronchitis and irritable cough, where it will soothe and reduce irritation whilst helping expectoration. Comfrey may be used externally to speed wound-healing and guard against scar tissue developing incorrectly. Care should be taken with very deep wounds, however, as the external application of Comfrey can lead to tissue forming over the wound before it is healed deeper down, possibly leading to abscesses. It may be used for any external ulcers, for wounds and fractures as a compress or poultice. It is excellent in chronic varicose ulcers. It has a reputed anti-cancer action.

Priest & Priest tell us that it is a “soothing demulcent, gently stimulating to the mucous membranes, allays irritation and encourages cell growth. Increases expectoration and tones the bronchi, especially suitable for conditions involving capillary haemorrhage or excessive mucous.” They give the following specific indications: coughs & colds, gastric & duodenal ulcers, gastro-intestinal inflammation, haemoptysis, haematemesis, pruritus ani, chronic suppurative ulcerations, bruised & damaged joints and muscles or pulled tendons, delayed union of fractures, traumatic injury to the eye.

Ellingwood recommends it for the following patholgies:bronchial irritation, pneumonia, inflammation of the stomach, and quotes `old European writers’ as being useful in all hurts and bruises both internal and external.

Combinations: For gastric ulcers and inflammations it combines well with Marshmallow and Meadowsweet. For chest and bronchial troubles use it with Coltsfoot, White Horehound or Elecampane. For wound healing use with Calendula.

Preparations & Dosage of Comfrey:

Decoction: put 1-3 teaspoonfuls of the dried herb in a cup of water, bring to the boil and let simmer for 10-15 minutes. This should be drunk three times a day.

Tincture: take 2-4 ml of the tincture three times a day.

Other uses of Comfrey:

Biomass, Compost, Gum

The plant grows very quickly, producing a lot of bulk. It is tolerant of being cut several times a year and can be used to provide ‘instant compost’ for crops such as potatoes. Simply layer the wilted leaves at the bottom of the potato trench or apply them as a mulch in no-dig gardens. A liquid feed can be obtained by soaking the leaves in a small amount of water for a week, excellent for potassium demanding crops such as tomatoes. The leaves are also a very valuable addition to the compost heap. A gum obtained from the roots was at one time used in the treatment of wool before it was spun.

Esoteric uses of Comfrey:

Magickal uses include money, safety during travel, and any Saturnian purpose. Use for workings involving stability, endurance, and matters relating to real estate or property. Put some in your luggage to help prevent loss or theft. Wear for travel safety and protection. Use the root in money spells and incenses.

The Chemistry:
  • Allantoin
  • Pyrrolizidine alkaloids, including echimidine, symphytine, lycopsamine, symlandine. The alkaloids are found in the fresh young leaves and in the root, but in two separate investigations were found to be absent in the dried herb.
  • Phenolic acids; rosmarinic, chlorogenic, caffeic and lithospermic acids.
  • Mucilage, about 29%, composed of a polysaccharide containing glucose &fructose.
  • Miscellaneous; choline, asparagine, volatile oil, tannins, steroidalsaponins, triterpenes


Citations from the Medline database for the genus Symphytum

ComfreyBehninger C Abel G Roder E Neuberger V Goggelmann W [Studies on the effect of an alkaloid extract of Symphytum officinale on human lymphocyte cultures]

Planta Med 1989 Dec;55(6):518-22 (Published in German)Brauchli J Luthy J Zweifel U Schlatter C Pyrrolizidine alkaloids from Symphytum officinale L. and their percutaneous absorption in rats.

Experientia 1982 Sep 15;38(9):1085-7Culvenor CC Clarke M Edgar JA Frahn JL Jago MV Peterson JE Smith LW Structure and toxicity of the alkaloids of Russian comfrey (symphytum xuplandicum Nyman), a medicinal herb and item of human diet.

Experientia 1980 Apr 15;36(4):377-9Fell KR Peck JM British medicinal species of the genus symphytum.

Planta Med 1968 May;16(2):208-16Franz G [Studies on the mucopolysaccharides of Tussilago farfara L., Symphytum officinalis L., Borago officinalis L. and Viola tricolor L]

Planta Med 1969 Aug;17(3):217-20 (Published in German)Gracza L Koch H Loffler E [Biochemical-pharmacologic studies of medicinal plants. 1. Isolation of rosmarinic acid from Symphytum officinale L. and its anti- inflammatory activity in an in vitro model]

Arch Pharm (Weinheim) 1985 Dec;318(12):1090-5 (Published in German)Hirono I Mori H Haga M Carcinogenic activity of Symphytum officinale.

J Natl Cancer Inst 1978 Sep;61(3):865-9Wagner H Horhammer L Frank U [Lithospermic acid, the antihormonally active principle of Lycopuseuropaeus L. and Symphytum officinale. 3. Ingredients of medicinal plants with hormonal and antihormonal-like effect]

Arzneimittel forschung 1970 May;20(5):705-13 (Published in German)