A Guide to Poisonous Plants

BLACK NIGHTSHADE (Solanum nigrum)

An erect branched annual plant, measuring from 10 cm to 60 cm. Common in cultivated land. The plant, particularly the berries, contain alkaloids, nitrates and nitrites. Symptoms include severe abdominal pain, staggering and depression.

BOX (Buxus sempervirens)

Native evergreen shrub or tree. Also cultivated as garden hedge plant. All parts are poisonous, but it tastes unpleasant. Steroidal alkaloids. Symptoms are diarrhoea, incoordination, convulsions, and coma. Respiratory failure causes death.

BRACKEN (Pteridium aquilinum)

Fern growing up to two metres. Common in England. Prefers acid soils and has a creeping root system. Is carcinogenic and contains an enzyme thiaminase, which leads to Vitamin B1 deficiency. Symptoms are incoordination and pronounced heartbeat after mild exercise with muscle tremors. Untreated these lead to convulsions and death. Treat with intravenous thiamine.

COWBANE (Cicuta virosa)

Erect perennial plant preferring damp conditions. Is localised in Britain. Roots contain concentrated higher alcohol cicutoxin, a convulsive poison. Poisoning occurs if roots are exposed (after ditching).

CUCKOO PINT (Arum maculatum)

Widely distributed in UK. Shade loving and persistent. Common names include “Lords and Ladies” and “Arum lily”. Juice of plant is an irritant. Ingested it causes swelling of mouth and neck, salivation and incoordination followed by collapse and death.

DEADLY NIGHTSHADE (Atropa belladonna)

Perennial of up to 1.5m, which is seldom eaten as it tastes unpleasant. Highly toxic with various alkaloids. Symptoms are dilated pupils and nervous excitement with an inability to stand.

FOXGLOVE (Digitalis purpurea)

Erect biennial of 150cm height found throughout Europe in hedges and gardens. Purple/red bell shaped flowers. Leaves contain cardiac glycosides. Symptoms include diarrhoea, abdominal pain, irregular pulse, tremors and convulsions.

HEMLOCK (Conium maculatum)

Branched perennial found in ditches and waste ground. Grows 2m or more in height. Stem has prominent purple spotting. Common in Europe. Contains highly toxic alkaloids causing paralysis and convulsions. Death is from respiratory paralysis.

HEMLOCK WATER DROPWORT (Oenanthe crocata)

Found throughout Britain on calcareous soils. Root has fleshy finger-like tubers, which give it its common name of “dead men’s fingers”. Convulsing poison requiring very small amounts to kill.

HORSETAIL (Equisetum spp.)

Vegetative stems of up to 80cm height. Found in damp grassy ground throughout Europe. Contains enzyme thiaminase (see Bracken) and ingestion leads to kidney damage.

IRIS (Iris pseudacorus/foetidissima)

Yellow and stinking Iris are found in Britain. All parts are poisonous. Symptoms include raised temperature and diarrhoea with some bleeding occasionally.

LABURNUM (Laburnum anagyroides)

Ornamental tree common in UK. Bright yellow flowers with pea like pods. Alkaloid poison in all parts of the tree. Symptoms are abdominal pain, high temperature, tremors, unsteady gait and convulsions. Fatal cases usually involve consumption of the seeds.

LARKSPUR (Consolida ajacis)

Larkspur or delphinium is cultivated throughout Britain. Usually not found wild but in gardens etc. Alkaloid poison causing agitation, breathing difficulties, incoordination, spasms and abdominal pain.

LILY OF THE VALLEY (Convallaria majalis)

Small perennial appears with white flowers in the spring. Native to Britain. Glycoside poisons. Symptoms include irregular pulse, excessive salivation with dilated pupils.

LINSEED (Linum usitatissimum)

Seed of the flax plant cultivated in Britain for its oil content and fibrous stem. Glycoside poison which blocks utilisation of oxygen and death occurs from brain failure. Symptoms include staggering, salivation, dilated pupils, gasping, rapid pulse and convulsions. Death can be rapid without symptoms displayed.

PRIVET (Ligustrum spp.)

There is a native species but it is most common as an ornamental evergreen hedge plant. Poisoning occurs as a result of eating clippings or browsing the hedge. Symptoms include paralysis, rapid pulse, congested mucous membranes and dilated pupils.

RAGWORT (Senecio jacobaea)

Abundant in Britain and noted as an injurious weed. An alkaloid poison, which may take months to produce symptoms or be rapid in effect. Animals suffer digestive problems with pain and diarrhoea, restlessness with incoordination and paralysis. It is more dangerous after drying in hay, as it is more palatable then. It should be sought out and dug up.

RHODODENDRON (Rhododendron ponticum)

Evergreen shrub common in Britain. Leaves, pollen and flowers are poisonous. Access to the plant is usually in parks, gardens etc. Symptoms include pain, salivation, diarrhoea or constipation, staggers, trembling with a weak pulse and slow irregular breathing followed by collapse.

YEW (Taxus baccata)

Evergreen tree native to Britain. Older trees are found in churchyards, as it was associated with religious activity. Toxic alkaloids, which affect the heart. All parts of the tree are poisonous except the berries. Symptoms are incoordination, coldness, rapid then weak pulse, excitability then collapse. Usually no symptoms are seen, as death is rapid.

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