This plant has traditionally been one of the principle remedies in any materia medica. Comfrey is an elegant plant, common to our inland waterways, and one of more than 25 species of coarsely hairy perennials within the genus.
The common name Comfrey is derived from the Latin ‘conferva’, (to join together) which begins to tell us how the Romans knew of and used the plant. Similarly, its scientific generic name also alludes to this ‘bringing together’ (sympho- from the Greek meaning to unite; phytum from the Latin, meaning plant), whilst the specific name officinale denotes its use as an official apothecary herb of old.
This plant is distinguished by its large, broadly lanceolate leaves (up to 30 cm long and more) which rise each year from a rhizomous rootstock. Its leaves are set on long, relatively thick petioles coming from the crown of the plant.
Comfrey initially grows as basal growth, but can we actually call that often untidy mass of leaves a rosette? Comfrey’s large leaves are coarse and hairy, with curving, and upward-sweeping, netted vein patterns, arising from the mid-vein. On the growing flowering stems the alternately spaced leaves have progressively shorter stalks, becoming sessile towards the top.
The leaves are quite similar to its family relative’s borage, lungwort, and the green-alkanet. Lungwort has white blotches on its leaves so cannot be readily mistaken for comfrey, though both borage and more especially the green alkanet could be. If you snap comfrey’s leaf stalks, the mucilaginous properties are quickly revealed.
One of the most dangerous misidentifications that a forager can make is mistaking comfrey for another well-known, also medicinally potent, yet poisonous and unrelated species – the foxglove. This plant belongs to the figwort family and has an extremely similar looking leaf to comfrey, even on second glance.
I have heard tales of inexperienced foragers picking foxglove leaves, then eating them in fritters, only to wake up a week later in hospital from a coma! This possibility should install some vital diligence in making absolutely sure of identification. To help in this, the reader is advised to become familiar with both plants.
The foxglove leaves will be seen to have minutely-crenate leaf margins, which comfrey does not have. Furthermore, the foxglove leaf veins do not curve out and sweep upwards. Rather, they rise at a more acute angle from the mid-rib.
It is also worth touching and holding the two plants. The two plants, whether it’s the leaves, stems, or petioles, all feel quite different to each other.
During flowering, the plants are much less likely to be confused. Many people will know the foxglove inflorescence. The glorious purple hooded flowers are borne on spikes and look totally different to comfrey’s inflorescence.
Another way of helping to distinguish comfrey and foxglove from afar is to observe and evaluate the habitat you are wandering through. If you are near streams or rivers or on wet ground below 320 metres, it is very likely the plant will be comfrey, for it delights in areas such as these.
Foxgloves can survive in sub-alpine conditions, and elevations of up to 1650 metres. The foxglove abounds by hedges, roadsides, and waysides, and especially by old, crumbling stone walls. They are often found within their classic lowland habitat of woodlands, where it will thrive at the edges, and within any well-lit glade.
The flowering stems of the common comfrey typically grow to about 150 cm high, although larger is not uncommon. Its flowers are borne on numerous cymes on multi-forked stalks. The flowers are usually creamy yellow-white on the wild comfrey, occasionally pink-purple.
Comfrey has distinctive, tubular or bell-shaped flowers, with a crenate finish to the fused petals. The seeds are little nutlets, which appear in groups of four. Comfrey’s root is thick and many-branched, from an often large crown. It has black skin with white flesh.
Comfrey self-propagates from its creeping rhizomes, and gardeners are advised to be careful when placing or removing common comfrey, for it will creep and take over patches of ground due to an ability to grow from any shards of root left in the ground. As a friend and I are all too aware, these quickly re-emerge and grow on.
A suitable comfrey cultivar for the garden can be acquired, which is known as ‘bocking 14′. This variety is clump forming and does not spread to anything like the same extent as our native species.
Parts used Leaves, roots.
Harvest Root in autumn, Leaves throughout season.
Key constituents Allantoin (up to 2.5%); tannins; mucilage; gums; resins; phytosterols; rosmarinic acid; pyrrolizidine alkaloids (including symphitine, cynoglosine, consolidine); inulin.
Actions Anti-inflammatory, vulnerary, demulcent, astringent, increases cell proliferation.
Pharmacology and uses Comfrey has been referred to as one of the chief plant medicines in the folk repertory of Britain and Ireland. It is an exceptionally effective mucilaginous healing remedy in any materia medica.
Comfrey has been popularly used for cuts, grazes, and lesions (though this is now discouraged), as well as to heal larger wounds, bone fractures, torn cartilage, tendons, and ligaments. The swift wound sealing action is mostly attributed to the allantoin, a recognised cell proliferant, and is partly due to the tannins and general astringency of the plant, enabling it to draw open wounds together.
The mucilage contains the remarkable allantoin. This substance is well known to promote constructive activity of different types of connective tissue such as chondroblasts (cartilage) and osteoblasts (bone) as well as flesh and skin. Allantoin also helps produce neural cells. It promotes keratin dispersal and has been used topically on psoriasis. Allantoin is highly diffusible and its presence means scarring is less likely.
It is because the plant heals cuts so quickly (but from the surface downwards), that comfrey is not recommended for deep cuts anymore. Instead, for these wounds, a number of other common vulnerary plants, such as plantains or yarrow can be more profitably employed. They will both ensure complete healing at the bottom of the wound, working upwards.
Be warned, because there are documented cases of comfrey being applied to baby girls as nappy rash ointments, that have then led to the vagina sealing up, such are its powers. As well as healing and sealing all types of tissue, comfrey also has a reputation for use on bruises and swellings. All parts of the plant yield an oily astringent juice, containing the mucilage, which can be readily applied as a poultice as well as being made into the classic comfrey ointment.
Traditional use for healing damaged limbs was by cleaning, peeling, grating, and then boiling the root. This process obtains a thick paste which is then applied like ‘plaster of paris’. The comfrey plaster acts much in the same way. It helps broken bones by setting the joint, whilst acting somewhat as a poultice, thus enabling the absorption of medicinal components from the outside inwards.
Of the folk records collected, almost half consistently refer to its use on fractures, sprains, and the like. Internal use of the root for the same problems is not documented, so please do not drink comfrey root thinking it will help set your broken bones as successfully. The tannins and resins actively combine with mucilage to help give rise to comfrey’s ‘plaster action’.
Much has been written about the dangers of liver damage resulting from internal use of the root due to it containing liver-toxic pyrrolizidine alkaloids. This group of around 660 alkaloids are found in a large number of plant species, approximately 6,000 worldwide. The PA causing the most concern in certain comfrey species, is echimidine.
Our native wild S.officinale typically has considerably smaller amounts of the toxic alkaloids than the very similar looking comfrey plant most people have in their gardens or allotments, the usually purple-flowering S. x uplandicum. Moreover it does not contain the notably harmful PA alkaloid echimidine in the leaf.
In North America and Canada, you can acquire over-the-counter comfrey remedies from Symphytum officinale, because it doesn’t contain echimidine. British Herbalists may still prescribe common comfrey leaf. In other comfrey species, the root can contain approximately up to 10 times as much PA’s as the leaf.
Suffice it to say here that the dangers of toxic doses from comfrey root, although cumulative in effect, remain very slim due to the minute amounts present per dose when used as medicine. Saying this, comfrey root is now contra-indicated by herbalists for internal use due to the alkaloids. Furthermore, European practitioners do not now recommend topical use on cuts and wounds.
S. x uplandicum is a cross between S.officinale and S.asperum (‘rough comfrey’) and will show typical hybrid vigour in a number of ways. One of these manifestations may well be the greater production of what are essentially predatory-defence chemicals in the bigger, more voracious hybrid plant.
The majority of tests carried out into alkaloid toxicity are based on direct subcutaneous injection of the alkaloids into rats, rather than testing the whole leaf or root. This does not replicate what actually occurs when we consume and digest the plant.
It is also worth reminding here that salicylic acid from meadowsweet could easily be as harsh to the stomach wall as aspirin, were it not for the other components present in the leaf (such as the mucilage and tannins) combining with it and providing healing incomparable to what aspirin can do.
I therefore continue to eat common comfrey occasionally, especially in the spring when it is at its best, as well as using it as a topical medicine, for musclular-skeletal injuries.
Comfrey has also been greatly used in the treatment of respiratory conditions and digestive ailments. A water extract of comfrey showed increases in the release of prostaglandins from the stomach wall. This has been suggested as producing a direct action in protecting the gastric mucosa from damage. Rosmarinic acid is also known for reducing inflammation and provides a major component of this plant’s anti-inflammatory action.
Comfrey is an exceptionally nourishing medicinal food, as was discovered in the 1970’s, containing as much protein as some legumes! The younger shoots and leaves are best used, and if steamed or blanched, offer a texture of succulent, slightly crunchy and mildly cucumber-tasting leaf stalks alongside the pleasant earthy ‘spinach’ taste of the leaf.
Alternatively, and perhaps more well known is using the leaves in a fritter. Simply make a batter and dip a folded leaf in, then fry. Served when golden brown with a sweetened chilli-enhanced soy sauce or such like, they are quite delicious.