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Rumex obtusifolius, broad-leaved dock

Summary

'Touch a nettle, get a dock' may be the best known piece of plant folklore but there is no evidence of anything other than a placebo effect.

Family

Polygonaceae

Meaning of the Name

Rumex
The circular definition, Latin for ‘sorrel’ seems to be the only one available.
 
obtusifolius
Latin ‘obtusi’, ‘blunt’ and ‘folium’, ‘leaf’ for the shape.

Common Names and Synonyms

broad-leaved dock, bitter dock.

How Poisonous, How Harmful?

The toxic component is calcium oxalates. These needle-shaped crystals can irritate the skin, mouth, tongue, and throat, resulting in throat swelling, breathing difficulties, burning pain, and stomach upset.

Oxalates in plants preferentially bind to calcium in the body. Regular ingestion in small amounts can lead to calcium deficiency and to the build up of kidney stones if the calcium oxalate formed is not excreted.

Its unattractive appearance combines with, as suggested by its alternative common name, its unpleasant taste to mean it is not a plant that is regularly consumed. 


Rumex obtusifolius, broad-leaved dock

Rumex obtusifolius, broad-leaved dock

Incidents

No reported incidents in humans but this and other species of Rumex have been associated with poisoning in sheep and cattle.

Folklore and Facts

Best known as the alleged antidote to nettle sting though there is no proof of its efficacy. It has been suggested that the dock is alkaline and counteracts the acidity of the nettle there is not even agreement that it is acidity in nettles which cause the sting.

'Touch a nettle, get a dock', however, is one of those beliefs where very few people occupy the centre ground. Most people either believe dock works in seconds or that it is of absolutely no value.

Dock provides another example of the misunderstandings behind many of the stories told by visitors to the Alnwick Garden Poison Garden. A visitor said that Native Americans smoke the leaves of Rumex and it is known as ‘Indian Tobacco’. According to the literature, Lobelia inflata is ‘Indian Tobacco’. This plant does look a bit like dock so that may be how the confusion arises.

Rumex obtusifolius is one of the five injurious weeds named in the 1959 Weeds Act and is very frequently seen in pasture land. One of the others is Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort, but the broad-leaved dock does not attract the same hysteria as is created by the ragwort.

IMPORTANT NOTE

The POISON GARDEN website is not connected with Alnwick Garden Enterprises Ltd and/or The Alnwick Garden Trust.

 

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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