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Poisonous plants

Name Toxic Parts Symptoms
Aconite All Nausea and vomiting.
Aloe Vera
Diarrhoea.
Alsike Clover
trifolium hybridum
All Causes female organs to swell, starts milk production without pregnancy, and can cause temporary or permanent infertility.
Amaryllis Bulbs Upset stomach, hyperactivity, lethargy, coma, and shock.
Angels' trumpets
Nausea and vomiting.
Apple seeds & apple pips Seeds Varied toxic effects. The plant is cyanogenic.
Apple leaf croton All Fatality (contains ricin), haemorrhages of the heart, degradation of the kidneys and liver, and intense inflammation and erosion of intestinal membranes.
Apricot Seed Fatality (contains cyanide).
Arborvitae
May cause skin allergies.
Asparagus fern
Contains a wide variety of poisons resulting in a bewildering range of symptoms.
Autumn crocus All Vomiting, nervous excitement, and dermatitis.
Avocado Fruit and pith Diarrhoea, vomiting, and laboured breathing.
Azalea All Nausea, vomiting, depression, difficulty breathing, and coma.
Barilla Leaves and stem Plant contains soluble oxalates.
Benweed
Senecio jacobaea

See Ragwort
Bird of paradise Seed Gastrointestinal tract affected by the plant's toxins.
Bittersweet All The plant is reputed to be toxic.
Black Locust
Robinia pseudoacacia
All, except the flowers Staggering and paralysis.
Black Walnut All Temporary paralysis.
Bleeding Heart
Dicentra Spectabilis
Foliage and roots Poisonous in large amounts. Contains convulsant including isoquinoline. Plant also causes dermatitis.
Blue bell
Harmful if eaten in quantity.
Boxwood All Upset stomach, heart failure, excitability or lethargy. Plant also causes dermatitis.
Branching ivy Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
British Manrake
Bryonia Dioica || See White Bryony
See White Bryony
Buckeyes
Aesculus hippocastanum
Nuts Gastrointestinal tract affected by saponins.
Buckthorn
Harmful if eaten in quantity.
Burning Bush All Nausea, vomiting, and skin allergies.
Buttercup
Ranunculus spp
All Juice may severely injure digestive system. Plant also causes dermatitis.
Caladium
Upset stomach, oral irritation, asphyxiation, tremors, seizures, and loss of balance.
Calico Bush
Nausea, vomiting, and skin allergies.
Calla lily Leaves Upset stomach, oral irritation, asphyxiation, tremors, seizures, and loss of balance.
Cannabis
cannabis sativa
All Muscular weakness, salivation, vomiting, and drowsiness - it is not generally fatal.
Castor bean
Ricinus communis L.
All A single Rosary Pea or one to two Castor Bean seeds can cause death. Plant also causes dermatitis.
Charming dieffenbachia Sap Repeated vomiting and diarrhoea (recovery after three days).
Cherry Seed Plant is cyanogenic.
Cherry Laurel
Harmful if eaten in quantity.
Chinese Lantern
Solanum spp || See Nightshade
See Nightshade
Christmas Cherry
Solanum spp
See Nightshade See Nightshade
Christmas rose All Upset stomach, diarrhoea, seizures, and disorientation. Cardiovascular system affected by the cardiac glycosides helleborin and helleborein. Plant also causes dermatitis.
Chrysanthemum Leaves and stem May cause a rash after contact. May cause dermatitis.
Clematis All Gastrointestinal tract and nervous system affected by plant toxins. Plant also causes dermatitis.
Cocklebur
Xanthium strumarium


Colombine
Harmful if eaten in quantity.
Common Nettle
urtica dioica
See Stinging Nettle See Stinging Nettle.
Common St. Johns Wort
hypericum perforatum || See St. Johns Wort
See St. Johns Wort   .
Common Stonecrop
sedum acre
All Salivation, muscle tremors, rapid respiration, and coma.
Cordatum

Corn cockle
Harmful if eaten in quantity.
Cuckoo pint
Nausea and vomiting. May cause a skin allergy.
Cutleaf philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Cyclamen Flowers Induced vomiting and a skin reaction.
Daffodil
Narcissus spp.
Bulbs Nausea, vomiting, and diarrhoea caused by the alkaloid toxins. Plant also causes dermatitis.
Daphne Berries and seeds Gastrointestinal tract and kidneys affected by coumarin glycosides. Plant also causes dermatitis.
Dwarf Bay See Mezereon See Mezereon.
Deadly Nightshade
Solanum spp
See Nightshade See Nightshade.
Delphinium
Delphinium spp.

Harmful if eaten in quantity.
Dendrathema
May cause a skin allergy.
Devils figs
Harmful if eaten in quantity.
Devil's Ivy
Philodendron
All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eat. Upset stomach, mouth irritation, tremors, seizures, loss of balance, asphyxiation, and death.
Dracaena palm

Dumb cane
dieffenbachia

Upset stomach, oral irritation, asphyxiation, tremors, seizures, loss of balance, and death.
Dutchman Breechs
Dicentra spp
See Bleeding Heart See Bleeding Heart.
Dwarf Morning glory
Harmful if eaten in quantity.
Easter lily

Echium
May cause a skin allergy.
Elderberry
Sambucus canadensis L.
All Nausea and vomiting. Plant is cyanogenic and may contain toxic levels of nitrates.
Elephant ears All Intense burning, irritation and swelling of the mouth and throat. Death can occur is tongue swells enough to block air passage.
English ivy
Hedera helix L.
Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
Ergot
Claviceps purpurea

Causes miscarriages in humans and sheep - there are suggestions that it would do the same in dogs.
European spindle
Harmful if eaten in quantity.
Exotica perfection dieffenbachia Sap Repeated vomiting and diarrhoea - recovery after three days.
False Acacia
Robinia pseudoacacia
See Black Locust See Black Locust.
False Hellebore
Nausea and vomiting.
Fescue
Festuca arundinaceae


Flannel flower
Harmful if eaten in quantity.
Flax
Harmful if eaten in quantity.
Foxglove
Digitalis purpurea L.

Cardiovascular system affected by the glycosides digitalin and digitoxin. Gastrointestinal tract affected by saponins.
Fruit salad plant
Philodendron
All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Gaultheria
Harmful if eaten in quantity.
Geranium
Mild dermatitis.
German ivy Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
German primula
Nausea and vomiting. May cause a skin allergy.
Giant dumb cane Sap Repeated vomiting and diarrhoea - recovery after three days.
Glacier ivy Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
Glory Lily
Causes nausea and vomiting.
Gold dieffenbachia Sap Repeated vomiting and diarrhoea - recovery after three days.
Golden chain tree All Excitement, staggering, convulsions, and coma. Nervous system affected by the alkaloid cytisine.
Granny's bonnets
Harmful if eaten in quantity.
Greater Burdock
Arctium lappa
Burs Burs to coats of dogs cause skin irritation - dogs remove burrs by licking, and the hooked scales penetrate the mucous membrane of mouth and tongue, leading to ulceration, oral discomfort, and salivation.
Hahn's self-branching English ivy Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
Heartleaf philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Hemp
Cannabis sativa L.
See Cannabis See Cannabis.
Henbane All Nausea and vomiting.
Holly Berries Upset stomach, tremors, seizures, and loss of balance.
Honeysuckle
lonicera periclymenum
Plants and berries Vomiting, diarrhoea, and lethargy.
Horse tail
Equisetaceace


Horse chestnut
Aesculus hippocastanum

Harmful if eaten in quantity.
Horse head philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Hurricane plant Bulb Varied toxic effects.
Hyacinth
Hyacinth orientalis
Bulb Gastrointestinal tract affected by alkaloid toxins. Plant also causes dermatitis.
Indian rubber plant

Iris Tubers Severe digestive upset. Gastrointestinal tract affected by the glycoside iridin. Plant also causes dermatitis.
Ivy
araliaceae
All Vomiting, diarrhoea, excitement, muscular spasms, and paralysis.
Jack in the Pulpit
Arisaema spp.
All Contains small crystals of calcium oxalate, causes burning to the mouth, and can cause hallucinations.
Japanese show lily

Japanese Spindle
Harmful if eaten in quantity.
Jessamine Berries and sap Digestive disturbance. Gastrointestinal tract affected by solanine glycoalkaloids. The nervous system affected by atropine-like toxins.
Jerusalem cherry
Solanum pseudocapsicum

Gastrointestinal tract affected by solanine glycoalkaloids. May contain toxic levels of nitrates. Plant may also cause dermatitis.
Jimson Weed
Datura stramonium L.
All Abnormal thirst, distorted sight, delirium, incoherence, and coma caused by the alkaloids atropine, scopolamine and hyoscyamine. May contain toxic levels of nitrates.
Johnsongrass

Kingcup
Harmful if eaten in quantity.
Lacy tree philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Larkspur Seeds Digestive upset, nervousness, and depression. Cardiovascular system affected by alkaloids including delphinine. Plant also causes dermatitis.
Latana
Lantana camara L.
Berries Affects lungs, heart, kidneys, and nervous system, affected by lantodene, an atropine-like toxin. Plant is also hepatogenic.
Laurel
Harmful if eaten in quantity.
Lenton rose
Harmful if eaten in quantity.
Leopard lily
Nausea and vomiting. May cause a skin allergy.
Leyland cypress
May cause a skin allergy.
Lily of the valley
Convallaria majalis
All Irregular heart beat and pulse accompanied by digestive upset and mental confusion caused by the glycosides convallarin and convallamarin.
Lobelia tupa
May cause a skin allergy.
Locust Bark, sprouts, and foliage Nausea and weakness.
Lupine
Lupinus spp


Mallow
Harmful if eaten in quantity.
Marsh marigold
Harmful if eaten in quantity.
Marble queen

Marijuana Leaves Plant contains the hallucinogens tetrahydro-cannabinols.
May apple
Podophyllum peltatum L.
Apple, roots, and foliage Severe diarrhoea. Contains 16 active toxic agents, mainly in the roots. Nervous system affected by plant toxins, also causes hematological abnormalities. Powdered root may cause conjunctivitis and keratitis.
Meadow rue
Harmful if eaten in quantity.
Meadow Saffron
Nausea and vomiting.
Mexican breadfruit

Mezereon
Lethargy, dizziness, vomiting, and diarrhoea.
Milkweed
Asclepias syriaca L.

May cause a skin allergy.
Mistletoe Berries, leaves, and stem Gastrointestinal tract affected by toxalbumins. Plant may also cause dermatitis. If ingested a few berries can be fatal to a puppy.
Monkshood All Digestive upset and nervous excitement. Cardiovascular system affected by alkaloid toxins.
Moonseed Berries Contains convulsant.
Morning glory
Upset stomach and hallucinations.
Moroccan broom
Harmful if eaten in quantity.
Mountain laurel
Harmful if eaten in quantity.
Naked Lady Lilly See Amaryllis See Amaryllis.
Narissus
Narcissus spp.
Bulbs Nausea, vomiting, and diarrhoea caused by the alkaloid toxins. Plant also causes dermatitis.
Needlepoint ivy Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
Nightshade
Solanum spp.
All Intense digestive disturbances.
Oak tree Foliage, acorns, and bark Poisoning by oak is usually seasonal, being most common in spring when the young buds or leaves are eaten and the autumn when the acorns are eaten. Oak
leaves and acorns contain tannic acid which is poisonous to horses and though eating a small number of leaves or acorns is almost certainly harmless, they can also be addictive, and once a horse has acquired a taste for them they can actively search them out. Also some animals seem to be more susceptible to oak poisoning than others with individual animals having different levels of tolerance. Oak poisoning causes gastroenteritis and kidney damage. Symptoms include: lack of appetite, staring coat, constipation followed by diarrhoea which may be bloodstained, abdominal pain depression, and blood in urine. There is no antidote. The horse is treated with drugs to reduce the pain and control the diarrhoea, antibiotics may be prescribed.
Oleander
Nerium oleander L.
All Affects the heart, produces severe digestive upset. Extremely poisonous, can cause death. Cardiovascular system affected by the glycosides oleandrin, oleandroside and nerioside. Plant may also cause dermatitis.
Onion All Causes anemia. Red urine, enlarged kidneys, and degeneration of liver.
Oriental lily

Ornamental Pepper
Solanum spp
See Nightshade See Nightshade.
Paspalum Seeds Dermatitis.
Pasque flower
Harmful if eaten in quantity.
Peace lily All Gastrointestinal tract affected by plant toxins. Plant also causes dermatitis.
Peach Stone and leaf Plant is cyanogenic.
Pencil cactus
Similar to LSD - hallucinogenic.
Peruvian lily
May cause a skin allergy.
Pineapple broom
Harmful if eaten in quantity.
Poison Hemlock
Conium maculatum L.
All Nervous system affected by alkaloids including coniine, conidrine, and coniceine. May contain toxic levels of nitrates. Plant also causes dermatitis.
Poinsettia Leaves and sap Diarrhoea, abdominal cramps, and delirium. Sap can cause irritation, and if rubbed in eyes - blindness. Gastrointestinal tract affected by the toxin euphorbin, may contain toxic levels of nitrates. Plant also causes dermatitis.
Poison ivy
Toxicodendron radicans (L.) Kuntze
Leaves, bark, and fruit May cause dermatitis.
Poison oak Leaves, bark, and fruit May cause dermatitis.
Poison sumac
Can cause severe blistering dermatitis if they come into contact with skin.
Poisonous Primula
Nausea and vomiting. May cause a skin allergy.
Pokeroot
Causing vomiting and nausea.
Pokeweed
Nausea and vomiting.
Poppy
Harmful if eaten in quantity.
Pothos All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Precatory bean Seeds Gastrointestinal tract affected by toxalbumins.
Primrose (primula) Leaves Upset stomach and may cause dermatitis.
Ragwort
Senecio jacobaea
All A common yellow flowered weed found in rough pasture and in some lawns. It is highly toxic to a wide variety of animals, especially horses and cattle, usually digested when dead as it becomes more palatable. However a number of dogs die  by eating a small amount whilst grazing on long grass. If you ensure that your lawns etc are kept free of the weed, and keep a check on dog grazing, the plant is obvious so it can be done easily.

Causes kidney failure and liver damage and is irreversible. Minute doses fatal, often wrongly diagnosed. Pyrrolizidine alkaloids cause hepatic veno-occlusive disease (Budd-Chiari syndrome) in humans

Note: In UK this plant is notifiable to MAFF due to its toxicity to livestock. If you have it on your land, please dig it up and dispose of it by burning. Do not leave it lying around as its toxicity increases. It must be dug up as the seeds can stay in the ground for a number of years.
Red Clover
trifolium pratense
See Alsike Clover See Alsike Clover.
Red-ink plant
Nausea and vomiting.
Red Maple

Rhododendron
Rhododendron spp.
All Nausea, vomiting, depression, difficulty breathing, and coma.
Rhubarb
Rheum Rhabarbarum
Leaves Large amounts of raw or cooked leaves can cause convulsions, coma and in extreme cases, death.
Rosary Pea
Ricinus communis L.
See Castor Bean See Castor Bean.
Rosebay
Nausea and vomiting.
Rose periwinkle
Harmful if eaten in quantity.
Rue
Nausea and vomiting. May cause a skin allergy.
Saddle leaf philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Satin pothos All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Savin
Harmful if eaten in quantity.
Schefflera
Nausea and vomiting. May cause a skin allergy.
Senecio

Silkweed
Harmful if eaten in quantity.
Silver pothos All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Solomon seal
Harmful if eaten in quantity.
Spotted dumb cane Sap Repeated vomiting and diarrhoea - recovery after three days.
Spurge Flax See Mezereon See Mezereon.
Spurge Olive See Mezereon See Mezereon.
Spurge Laurel
Nausea and vomiting. May cause a skin allergy.
Squill
Harmful if eaten in quantity.
Staggerweed
Senecio jacobaea
See Ragwort See Ragwort.
Star of Bethlehem
Harmful if eaten in quantity.
Starflower
Harmful if eaten in quantity.
Stinging nettle
urtica dioica
Leaves In very extreme cases, trembling, vomiting, difficulty in breathing, and weakness.
St James Wort
Senecio jacobaea
See Ragwort See Ragwort.
St Johns Wort
hypericum perforatum
All Symptom lesions develop on un-pigmented areas of skin exposed to sunlight - photosensitization.
Subterranean Clover
trifolium subterranium
See Alsike Clover See Alsike Clover.
Sweetheart ivy Berries and leaves Gastrointestinal tract affected by saponins. Plant also causes dermatitis.
Swiss cheese plant Sap Repeated vomiting and diarrhoea - recovery after three days.
Tansy
Senecio jacobaea
See Ragwort See Ragwort.
Taro vine All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth irritated by plant raphides.
Thorn Apple See Jimson weed See Jimson weed.
Tiger lily

Tomato plant Fruit, stem, and leaves
Tree philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Tropic snow dieffenbachia Sap Repeated vomiting and diarrhoea - recovery after three days.
Tulip
Tulipa spp

May cause a skin allergy.
Variegated philodendron All Causes diarrhoea upon ingestion. Also causes dermatitis when touched. Causes burning sensation in mouth when eaten.
Variegated rubber plant

Varnish tree
Poisonous. Can cause severe blistering dermatitis if they come into contact with skin.
Water Hemlock
Cicuta maculata
All Violent painful convulsions, death caused by the convulsant cicutoxin.
White Bryony
bryonia dioica
Roots Possible increase in body temperature, rapid respiration, and high heart rates.
White Clover
trifolium repens
See Alsike Clover See Alsike Clover.
Wild Cherry tree Foliage Gasping, excitement, and prostration. Contains a compound that releases cyanide when eaten.
Wild Pepper See Mezereon See Mezereon.
Wisteria All Digestive upset caused by alkaloid toxins. Nausea, repeated vomiting, stomach pains, severe diarrhoea, dehydration, and collapse.
Wolfs bane
Nausea and vomiting.
Woody Nightshade
Nausea and vomiting.
Yew Berries and foliage Digestive disturbance, dizziness, dry mouth and mydriasis develop within one hour, followed by abdominal cramping, salivation and vomiting. Foliage is more fatal than berries, death can be sudden without warning or symptoms.