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Symphytum spp., comfrey


Symphytum, comfrey

Formerly much valued as a herbal remedy but not now recommended for ingestion though application to the skin is, probably, harmless.



Meaning of the Name

From the Greek, ‘sympho’, ‘to unite’ resulting from the plant’s alleged ability to knit bones together.
From the Caucasus Mountains.

Common Names and Synonyms


Symphytum spp., comfrey

Symphytum spp., comfrey

How Poisonous, How Harmful?

Contains pyrrolidizine alkaloids including heliosupine and cynoglosine. The young leaves contain a highish concentration which is reduced as the leaves enlarge and age.

Trials have suggested that ingestion of 6kgs of comfrey would be necessary to cause severe liver damage. Even so, ingestion as a herbal remedy is not recommended. The same tests found that absorption through the skin is twenty to fifty times less efficient than ingestion so comfrey creams offered as herbal remedies are unlikely to cause any problems.


The only known incidents relating to comfrey result from excessive use of herbal capsules or tea.

Folklore and Facts

Symphytum, comfrey

John Gerard said of the benefits of the plant ‘The slimie substance of the roote made in a posset of ale, and given to drinke against the paine in the backe, gotten by any violent motion, as wrestling, or over much use of women, doth in fower or five daies perfectly cure the same, although the involuntarie flowing of the seed in men be gotten thereby.’

‘Symphytum’ comes from a Greek word meaning ‘to knit together’. It does contain allantoin, a substance which is said to increase cell generation but the presence of pyrrolizidine alkaloids makes it dangerous to ingest. Some sources suggest that even in ‘beneficial’ amounts, ingestion of comfrey for more than five days could cause permanent liver damage in children.

The work on the effects of the pyrrolizidine alkaloids in Symphytum species is of interest in the context of Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort, for two reasons. The concentration of PAs in both genera is broadly similar so the results for comfrey can be read across to ragwort. This is particularly important given the persistence of the lies about skin absorption of ragwort. But, there is also the point that this work was done on comfrey, where its use in herbal preparations creates an identifiable concern, and not on ragwort where the concerns are, largely, hysterical.


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Introduction to the A to Z section
Abrus precatorius, rosary pea
Aconitum lycoctonum, wolfsbane
Aconitum napellus, monkshood
Actaea racemosa, black cohosh
Actaea spicata, baneberry
Aesculus hippocastanum, horse chestnut
Amanita muscaria, fly agaric
Aquilegia atrata, columbine
Aristolochia clematitis, birthwort
Artemisia absinthium, wormwood
Arum italicum, Italian cuckoopint
Arum maculatum, cuckoopint
Aspergillus fumigatus
Atropa belladonna, deadly nightshade
Brugmansia suaveolens, angel's trumpet
Bryonia dioica, bryony
Buxus sempervirens, common box
Camellia sinensis, tea
Cannabis sativa, marijuana
Catha edulis, khat
Chelidonium majus, greater celandine
Cimicifuga racemosa, black cohosh
Claviceps purpurea, ergot
Clematis vitalba, old man's beard
Colchicum autumnale, naked ladies
Conium maculatum, poison hemlock
Convallaria majalis, lily of the valley
Cynoglossum officinale, hound’s tongue
Daphne mezereon, spurge olive
Datura stramonium, thorn apple, jimsonweed
Datura suaveolens, angel's trumpet
Delphinium, larkspur
Digitalis spp., foxglove
Dracunculus vulgaris, dragon arum
Echium vulgare, viper’s bugloss
Eranthis hyemalis, winter aconite
Erythroxylum coca, cocaine
Euonymus europaeus, spindle tree
Euphorbia x martinii, red spurge
Euphorbia pulcherrima, poinsettia
Fritillaria spp., fritillary
Galanthus nivalis, snowdrop
Hedera helix, common ivy
Helleborus spp., hellebore
Heracleum mantegazzianum, giant hogweed
Hyacinthoides non-scripta, bluebell
Hyoscyamus niger, black henbane
Ilex aquifolium, holly
Jacobaea vulgaris, ragwort
Juniperus communis, common juniper
Laburnum anagyroides, laburnum
Lactuca serriola, prickly lettuce
Leucojum aestivum, snowflake
Lithospermum officinale, gromwell
Lolium temulentum, darnel
Malus 'John Downie', crab apple
Mandragora officinarum, mandrake
Mercurialis perennis, dog’s mercury
Narcissus, daffodil
Nepeta faassenii, catmint
Nerium oleander, oleander
Nicotiana sylvestris, tobacco
Oenanthe crocata, hemlock water dropwort
Papaver somniferum, opium poppy
Pastinaca sativa, parsnip
Polygonatum odoratum, angular Solomon's seal
Prunus laurocerasus, cherry laurel
Pulsatilla vulgaris, pasque flower
Ranunculus acris, meadow buttercup
Rheum x hybridum, rhubarb
Rhododendron spp.
Rhus radicans, poison ivy
Ricinus communis, castor oil plant
Rosmarinus officinalis, rosemary
Rumex obtusifolius, broad-leaved dock
Ruta graveolens, rue
Salix alba, white willow
Salvia divinorum, sage
Scutellaria laterifolia, Virginian skullcap
Senecio jacobaea, ragwort
Solanum dulcamara, woody nightshade
Solanum melongena, aubergine
Strychnos nux-vomica, poison nut
Symphoricarpos albus, snowberry
Symphytum spp., comfrey
Taxus baccata, yew
Toxicodendron radicans, poison ivy
Thevetia peruviana, yellow oleander
Urtica dioica, stinging nettle
Veratrum album, white hellebore
Verbascum olympicum, Greek mullein
Vinca major, greater periwinkle
Viscum album, mistletoe
Vitex agnus-castus, chaste tree