Botanical Name

Common Name

Dangerous Plant Parts, Symptoms

Aconitum napellus

Monkshood

Entire plant; causes cardiac arrhythmia, speech difficulties, salivation, nausea, visual blurring, tingling and burning of the lips, tongue, mouth and throat, followed by numbness and constriction

Aesculus spp.

Horse chestnut

Young shoots, leaves flowers and mature nuts; causes severe gastroenteritis leading to electrolyte imbalance. Usually fatal after multiple exposures

Anemone spp.

Anemone

Varies by species, but generally entire plant; causes severe irritation and blistering of the mucous membranes. If swallowed, causes internal bleeding

Arnica montana

Mountain tobacco

Flowers and roots; causes hemorrhage, prostration, chills and body aches

Arum maculatum

Cuckoo-pint

Entire plant; colourful orange berries may cause esophagal swelling. Calcium oxalates cause irritation and swelling of mouth and throat. If eaten, it can cause impaired blood clotting, vomiting and diarrhea.

Atropa belladonna

Belladonna

Entire plant, but berries are extremely dangerous; causes dry mouth, voice loss, tachycardia, elevated temperature and blurred vision. Also causes inability to pass urine.

Bulbocodium vernum,
Colchicum vernum

Spring meadow saffron

Entire plant, especially seed and bulbs; causes burning of the mouth and throat, intense thirst, nausea, vomiting and severe diarrhea. Occasional involvement of kidneys and dehydration is a danger

Calycanthus fertilis

Sweetshrub

Seed; causes convulsions, myocardial depression and hypotension

Calycanthus floridus

Carolina allspice

Seed; causes convulsions, myocardial depression and hypotension

Calycanthus occidentalis

Californian allspice

Seed; causes convulsions, myocardial depression and hypotension

Chelidonium majus

Celandine

Entire plant; produces acrid juice. Causes depression of parasympathetic systems

Clematis spp.

Clematis

Varies by species, but generally entire plant; causes irritation and blistering of skin and mucous membranes, salivation, bloody vomiting and diarrhea, abdominal cramps, dizziness and convulsions

Colchicum autumnale

Autumn crocus

Entire plant, especially seed and bulbs; causes burning of the mouth and throat, intense thrist, nausea, vomiting and severe diarrhea. Occasional involvement of kidneys and dehydration is a danger.

Colchicum speciosum

Crocus

Entire plant, especially seed and bulbs; causes burning of the mouth and throat, intense thrist, nausea, vomiting and severe diarrhea. Occasional involvement of kidneys and dehydration is a danger.

Convallaria majalis

Lily-of-the-valley

Entire plant; causes a rash, heart arrhythmia and gastrointestinal distress. Could kill someone with a heart problem.

Daphne spp.

Daphne

Entire plant, especially fruit; causes blistering and swelling of lips, mouth and throat. Also causes salivation, thirst, abdominal pain, vomiting, bloody diarrhea and loss of electrolytes. May cause kidney damage.

Delphinium spp.

Larkspur

Varies by species, but generally young leaves and seed; causes gastroenteritis and dysfunction of the nervous system

Dicentra spp.

Bleeding heart

Entire plant; fatal in large quantities, but causes temporary coma-like states and labored breathing and convulsions.

Digitalis purpurea

Foxglove

Flowers, leaves and seed; affects the heart rate and causes pain, nausea, vomiting, cramps, diarrhea and convulsions.

Euonymus americanus

Strawberry bush

Entire plant; causes a delayed onset of symptoms, including diarrhea, persistent vomiting and convulsions

Euonymus atropurpureus

Burning bush

Entire plant; causes a delayed onset of symptoms, including diarrhea, persistent vomiting and convulsions

Euonymus europaeus

European spindle tree

Entire plant; causes a delayed onset of symptoms, including diarrhea, persistent vomiting and convulsions

Euphorbia lathyrus

Mole plant

Seed; very corrosive to membranes and skin, causes acute gastritis. Milky juice is an extreme irritant.

Helleborus niger

Christmas rose

Entire plant; causes heart arrhythmia

Hydrangea spp.

Hydrangea

Flower buds; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions

Kalmia angustifolia

Dwarf laurel

Entire plant (even small amounts of leaves may be fatal); causes transient mouth burning. After a few hours, causes salivation, diarrhea, vomiting, prickling of skin, headaches, severe hypotension, come and convulsions.

Kalmia latifolia

Mountain laurel

Entire plant (even small amounts of leaves may be fatal); causes transient mouth burning. After a few hours, causes salivation, diarrhea, vomiting, prickling of skin, headaches, severe hypotension, come and convulsions.

Laburnum spp.

Goldenchain tree

Entire plant, especially fruit; causes rapid onset of vomiting, drowsiness, weakness, incoordination, sweating, pallor, headaches and tachycardia

Leucothoe spp.

Sweet bells

Leaves and honey from nectar; causes brief burning of mouth. Hours later causes salivation, vomiting, diarrhea, prickling of skin, headaches, weakness, dim vision, hypotension, coma and convulsions.

Ligustrum ovalifolium

California privet

Leaves and berries; causes colic, vomiting, diarrhea, gastroenteritis and dehydration

Ligustrum vulgare

Common privet

Leaves and berries; causes colic, vomiting, diarrhea, gastroenteritis and dehydration

Lobelia cardinalis

Cardinal flower

Entire plant; causes rapid onset of vomiting, drowsiness, weakness, incoordination, sweating, pallor and tachycardia

Lobelia inflata

Indian tobacco

Entire plant; causes rapid onset of vomiting, drowsiness, weakness, incoordination, sweating, pallor and tachycardia

Lobelia siphilitica

Great lobelia

Entire plant; causes rapid onset of vomiting, drowsiness, weakness, incoordination, sweating, pallor and tachycardia

Lonicera spp.

Honeysuckle

Varies by species, berries; causes severe and persistent vomiting, colic, diarrhea, shock, cardiac arrhythmia, twitching, convulsions and respiratory failure.

Lyonia spp.

Huckleberry

Leaves and nectar; causes brief burning of mouth. Hours later, causes salivation, vomiting, diarrhea, prickling sensation, headaches, weakness, dim vision, hypotension, coma and convulsions.

Malus sylvestris

Apple

Seed; in large quantities can cause cyanide poisoning. Also causes abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Melia azadarach

Chinaberry

Entire plant; causes delayed onset of symptoms, including faintness, ataxia, mental confusion, intense gastritis, and vomiting and diarrhea leading to shock. Also causes labored respiration, convulsions, paralysis, fatty degeneration of the liver and kidney failure.

Menispermum canadense

Moonseed

Fruit in large quantities; causes convulsions

Narcissus spp.

Daffodil

Bulbs in large quantities; cause nausea, persistent vomiting and dehydration

Nerium oleander

Oleander

Entire plant; causes mouth pain, nausea, vomiting, abdominal pain, cramps, diarrhea and frequent heart attacks

Nicotiana glauca

Tree tobacco

Leaves and flowers; causes salivation, vomiting, sensation of sweating, sensory disorders, convulsions and vasomotor collapse (breathing stops)

Nicotiana tabacum

Tobacco

Leaves and flowers; causes salivation, vomiting, sensation of sweating, sensory disorders, convulsions and vasomotor collapse (breathing stops)

Papaver somniferum

Opium poppy

Unripe seed capsules; causes a narcotic overdose and depression of parasympathetic systems

Parthenocissus quinquefolia

Virginia creeper

Fruit; causes severe gastroenteritis

Pernettya spp.

Pernettya

Leaves and nectar; causes transient mouth burning. Hours later, causes salivation, diarrhea, vomiting, prickling of skin, headaches, severe hypertension, coma and convulsions.

Phytolacca americana

Pokeweed

Older leaves and fruit, but roots are the most dangerous; causes delayed onset of symptoms, including nausea, cramps, profuse sweating, persistent vomiting, diarrhea and dehydration.

Pieris floribunda

Lily-of-the-valley shrub

Leaves and nectar; causes transient mouth burning. Hours later, causes salivation, diarrhea, vomiting, prickling of skin, headaches, severe hypertension, coma and convulsions.

Pieris japonica

Japanese pieris

Leaves and nectar; causes transient mouth burning. Hours later, causes salivation, diarrhea, vomiting, prickling of skin, headaches, severe hypertension, coma and convulsions.

Podophyllum peltatum

May apple

Entire plant and resin except the ripe fruit; causes intense diarrhea, come and kidney failure.

Prunus armeniaca

Apricot

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Prunus avium

Sweet cherry

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Prunus caroliniana

Cherry laurel

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Prunus laurocerasus

English laurel

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Prunus pennsylvanica

Pin cherry

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Prunus persica

Peach

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Prunus serotina

Black cherry

Wilted leaves, broken twigs, broken fruit pits; causes cyanide poisoning, abdominal pain, vomiting, lethargy, sweating, coma and convulsions.

Rheum x cultorum
Rheum rhabarbarum

Rhubarb

Leaves; causes extreme diarrhea and kidney failure due to oxalates

Rhododendron spp.

Rhododendron

Entire plant, including the nectar; causes transient mouth burning. Hours later, causes salivation, diarrhea, vomiting, prickling of skin, headaches, severe hypotension, coma and convulsions.

Ricinus communis

Castor bean plant

Entire plant, especially seed; causes a delayed onset of symptoms, including nausea, vomiting, diarrhea, dehydration and intestinal dysfunction. One seed can kill a small child.

Skimmia japonica

Japanese skimmia

Entire plant, the red fruit is the usual cause of poisoning; causes cardiac arrest

Taxus baccata

Yew

Foliage, broken seed and bark, although toxicity varies for each plant; causes dizziness and dry mouth within an hour, then causes abdominal cramps, salivation, vomiting and possibly rash. Also causes face to pale, blue lips, weakness, heart arrhythmia, hypotension, and cardiac or respiratory failure.

Taxus canadensis

Canadian yew

Foliage, broken seed and bark, although toxicity varies for each plant; causes dizziness and dry mouth within an hour, then causes abdominal cramps, salivation, vomiting and possibly a rash. Also causes face to pale, blue lips, weakness, heart arrhythmia, hypotension, and cardiac or respiratory failure.

Taxus cuspidata

Japanese yew

Foliage, broken seed and bark, although toxicity varies for each plant; causes dizziness and dry mouth within an hour, then causes abdominal cramps, salivation, vomiting and possibly a rash. Also causes face to pale, blue lips, weakness, hearth arrhythmia, hypotension, and cardiac or respiratory failure.

Veratrum spp.

False hellebore

Entire plant; fatal only in large quantities, but causes cardiac symptoms, burning sensation and pain in upper abdomen, salivation, nausea, vomiting, sweating, blurred vision and confusion. Feels like a heart attack.