Poisonous Plants

Common Name/ Scientific Name	Plant Type	Part of Plant	Degree of Toxicity, Cumulative?	Poisonous Compound	Livestock Effects
Arrowgrass (Triglochin maritima)		All	Can be severe	Glycosides (produce cyanide)	Under some conditions can cause illness & death in livestock.
Baneberry (Actaea rubra)	Forb	All, esp. roots & berries	Moderate - Severe	Protoamemonin and probably a glycoside or essential oil	Stomach cramps, dizziness, vomiting, circulatory failure, headache. European species have caused death.
Bleeding-Heart (Dicentra spp.)	Forb	All	Mild - Moderate	Alkaloids	Trembling, agitation, heavy salivation, vomiting, diarrhea, convulsions, difficult breathing
Boxwood (Buxus sempervirens)	Shrub	All	Moderate - Severe	Steroidal alkaloids (buxine)	Abdominal pains, vomiting, diarrhea. Large doses can cause convulsions, coma, and death.
Bracken Fern (Pteridium aquilinum)	Fern	All	Mild - Severe, Cumulative	Thiaminase enzyme, carcinogens, often glycosides (prunasin)	Thiamine deficiency, which can be fatal. Cumulative effects may include cancer. Poisonous compounds can pass into milk.
Buttercups (Ranunculus spp.)	Forb	All	Mild - Moderate	Protoanemonin from ranunculin glycoside	Inflammation and blistering of skin, gastrointestinal irritation. Usually only present in fresh plants, not dried.
Camas, Death (Zigadenus venenosus)	Forb	All	Severe	Steroidal glycosidal alkaloid	Salivation, weakness, respiratory difficulty, nausea, convulsions, coma, death.
Cherry, Choke (Prunus virginiana)	Tree	Seeds, leaves, bark	Moderate - Severe	Cyanogenic glycoside (produces cyanide)	Initial rapid breathing followed by slow, difficult breathing, anxiety, excitement, confusion, headache, vomiting, dizziness, can cause death. Other related species which may be poisonous include mountain ash (Sorbus spp.), Hawthornes (Crataegus spp.), Pyracantha, Cotoneaster.
Clematis (Clematis spp.)	Vine	All	Mild - Moderate	Protoanemonin from ranunculin glycoside	Inflammation and blistering of skin, gastrointestinal irritation. Usually only present in fresh plants, not dried.
Cocklebur (Xanthium strumarium)	Forb	All, esp. seeds & seedlings	Moderate - Severe	Glycosides	Loss of appetite, vomiting, weakness, ataxia, spasms, in severe cases, death.
Crocus, Autumn (Colchicum autumnal)	Forb	All, esp. bulb and seeds	Moderate - Severe	Alkaloids (colchiceine)	Burning pain in the mouth and throat, nausea, vomiting, diarrhea, lethargy, low blood pressures, shock, convulsions, coma, death (with larger doses).
Cucumber, Wild (Marah oreganus)	Vine	Fruit	Mild - Severe	Saponic glycosides	Chest pains, shortness of breath, can cause death.
Daffodil and Narcissus (Narcissus spp.)	Forb	All, esp. bulbs	Moderate - Severe	Alkaloids (glycoside)	Dizziness, abdominal pain, nausea, vomiting, diarrhea. Large doses can cause trembling, convulsions, and death.
Domestic Plums, cherries, peaches, apricots, apples, pears (Prunus spp., Manus spp. Pyrus spp.)		Seeds, leaves, bark	Mild - Moderate	Cyanogenic glycoside (produces cyanide)	Initial rapid breathing followed by slow, difficult breathing, anxiety, excitement, confusion, headache, vomiting, dizziness, can cause death in large quantities. Toxicity may be variable. Other related species which may be poisonous include mountain ash (Sorbus spp.), Hawthornes (Crataegus spp.), Pyracantha, Cotoneaster.
Elderberry (Sambucus spp.)	Shrub	Leaves, stems, bark, and roots	Mild - Moderate	Alkaloid and cyanogenic glycoside (produces cyanide)	Nausea, vomiting, diarrhea. Raw fruits can cause nausea.
European bittersweet (Solanum delcamara)	Vine	All, especially green berries	Moderate - Severe	Alkaloidal glycoside (Solanine)	Abdominal pain, headache, flushed skin, tiredness. Severe cases include vomiting, thirst, difficult breathing, paralysis, dilated pupils, diarrhea, can cause death. Green potatoes contain the same chemical but in lower concentrations.
Fiddleneck or Tarweed (Amsinckia sp.)	Forb	All	Moderate, Cumulative	Thiaminase, Pyrrolizidine alkaloids	Appetite loss, timid, stupified, incoordination, liver lesions, enlarged liver (same as Tansy Ragwort)
Foxglove (Digitalis purpurea)	Forb	All	Severe	Digitoxin and other glycosides	Contracted pupils, nausea, vomiting, cramps, severe headache, irregular heartbeat, labored breathing, convulsions, death, usually a problem only in hay.
Golden Chain (Laburnum anagyroides)	Tree	All, esp. bark and seeds	Moderate - Severe	Alkaloid (systine) - similar effects to nicotine	Nausea, vomiting, abdominal pain, diarrhea, drowsiness, headache, dizziness, fever, irregular heartbeat, dilated pupils. Severe cases can have convulsions, coma and death. the toxicity varies widely.
Groundsel, Common (Senecio vulgaris)	Forb	All	Moderate, Cumulative	Pyrrolizidine alkaloids	Liver lesions, enlarged liver, abdominal pain, weakness, staggering, death. Liver damage is permanent. Usually only eaten in hay or when wilted. Drying or storage doesn't destroy toxins.
Hellebore, False (Veratrum spp.)	Forb	All, esp. the rhizome	Moderate - Severe	Alkaloids	Abdominal pain, vomiting, diarrhea, paralysis, spasms. In severe cases can cause death. Can cause birth defects if eaten during certain gestation periods.
Hemlock, Poison (Conium maculatum)	Forb	All	Severe	Coniine and other alkaloids	Teeth grinding, muscle spasms, respiratory failure, death.
Hemlock, Water (Cicuta spp.)	Forb	All, esp. root	Severe	Cicutoxin	Nausea, salivation, vomiting, convulsions, fever, low heart rate, abdominal pain, dilated pupils, delirium, coma, respiratory paralysis, death. Water Parsley (Oenanthe spp.) may contain similar toxin.
Holly, English (Ilex aquifolium)	Shrub	Berries, leaves	Mild	Glycosides and alkaloids	Nausea, vomiting, diarrhea, drowsiness.
Horse Chestnut (Aesculus hippocastanum)	Tree	All	Moderate - Severe	Saponin glycoside, alkaloids	Inflammation of mucous membranes, vomiting, thirst, weakness, muscular twitching, dilated pupils, stupor, paralysis. Coma and death can occur in severe cases.
Horsetail (Eqisetum arvense)	Fern - ally	All	Mild - Moderate, Cumulative	Thiaminase	Destroys vitamin B1. Symptoms include weight loss, weakness, eventual death.
Iris or Yellow Flag (Iris pseudacorus)	Forb	All, esp. rhizomes	Moderate - Severe	Glycoside	Abdominal pain, nausea, vomiting, diarrhea, spasms, staggering, paralysis.
Ivy, English (Hedera helix)	Vine	All, esp. leaves and berries	Moderate	Triterpene saponins (glycosides)	Large quantities cause vomiting, diarrhea, spasms, staggering, paralysis.
Knapweed, Russion and Yellowstar Thistle (Centaurea spp.)	Forb	All	Moderate, Cumulative		Brain deterioration resulting in "Chewing disease", can eventually cause death by starvation.
Knotweeds (Polygonum spp.)	Forb	All	Mild	Oxalic Acid	Large quantities can cause interference with calcium metabolism in the body and possible phototoxicity.
Lambsquarters (Chenopodium album)	Forb	All	Mild	Oxalates	Large quantities can cause interference with calcium metabolism in the body and possible phototoxicity.
Larkspur (Delphinium spp.)	Forb	All	Severe	Alkaloids (delphinine)	Constipation, bloat, dilation of pupils, vomiting, depression, paralysis, death.
Laurel, English (Prunus laurocerasus)	Shrub	Seeds, leaves, bark	Mild - Moderate	Cyanogenic glycoside (produces cyanide)	Initial rapid breathing followed by slow, difficult breathing, anxiety, excitement, confusion, headache, vomiting, dizziness, can cause death in large quantities. Toxicity may be variable. Other related species which may be poisonous include mountain ash (Sorbus spp.), Hawthornes (Crataegus spp.), Pyracantha, Cotoneaster.
Lily of the Valley (Convallaria majalis)	Forb	All	Severe	Cardiac glycosides (digitalis-like)	Burning pain in mouth and throat, salivation, nausea, vomiting, abdominal pain, headache, dilated pupils, slow and irregular heartbeat, sometimes coma and death.
Locust, Black or Honey (Robinia pseudoacacia)	Tree	All	Mild - Moderate	Poisonous Proteins	Lassitude, nausea, vomiting, abdominal pain, diarrhea, delirium, coma, death in livestock in severe cases.
Lupine (Lupinus spp.)	Forb	All	Moderate, Cumulative	Alkaloids (lupinine)	Birth defects, spasms, vomiting, nausea, dizziness, headache, abdominal pain, and in severe cases, death.
Nightshade, Black (Solanum nigrum) Nightshade, Hairy (Solanum sarrachoides)	Vine	All, especially green berries	Moderate - Severe	Alkaloidal glycoside (Solanine)	Abdominal pain, headache, flushed skin, tiredness. Severe cases include vomiting, thirst, difficult breathing, paralysis, dilated pupils, diarrhea, can cause death. Green potatoes contain the same chemical but in lower concentrations.
Oak (Quercus spp.)	Tree	All, but esp. acorns	Slight	Tannins (?)	Constipation, blood in urine.
Pea, Wild; Sweet Pea (Lathyrus spp.)	Forb	Foliage, Seeds	Mild	Toxic amino acids	Paralysis, convulsions, death. Toxic only in large quantities.
Pigweed (Amaranthus spp.)	Forb	All	Mild	Oxalates, nitrates	Large doses can cause fluid accumulation around kidneys.
Poison Oak, Poison Ivy (Toxicodendron spp.)	Shrub / Vine	All	Mild - Moderate, Cumulative	Oleoresin (urushiol)	Itching, burning, redness of skin, blisters.
Ponderose Pine (pinus ponderosa)	Tree	Needles	Mild - Moderate		Abortion
Ragwort, Tansy (Senecio jacobea)	Forb	All	Moderate, Cumulative	Pyrrolizidine alkaloids	Liver lesions, enlarged liver, digestive disturbances, restlessness, lack of coordination, weakness, staggering, death. Liver damage is permanent. Usually only eaten in hay or when wilted. Drying or storage doesn't destroy toxins. Toxins can contaminate milk and honey.
Rhododendron (Rhododendron spp.)	Shrub	All	Mild - Severe	Glycosides	Burning of lips, mouth, salivation, nausea, severe vomiting, coma and death in the most severe cases. The toxin can contaminate honey.
Rhubarb (Rheum rhabarbarum)	Forb	Leaves	Moderate	Oxalic acid and oxalates (irritant poison)	Abdominal pain, nausea, vomiting, difficulty breathing, drowsiness, large doses can cause convulsions, coma and death. Oxalic acid interferes with calcium metabolism as well.
Scotch Broom (Cytisus scoparius)	Shrub	All	Mild - Moderate	Quinolizidine	Nausea, vomiting, dizziness, headache, abdominal pain.
Serviceberry (Amalanchier alnifolia)	Shrub	Leaves, twigs	Mild - Moderate	Cyanogenic glycoside (produces cyanide)	Initial rapid breathing followed by slow, difficult breathing, anxiety, excitement, confusion, headache, vomiting, dizziness.
Skunk Cabbage (Lysichitum americanum)	Forb	All	Mild - Moderate	Calcium oxalate crystals	Physical irritation and swelling of mouth, throat, etc. as crystals pierce the skin.
Snowberry (Symphoricarpos albus)	Shrub	Berries	Moderate - Severe	Alkaloids	Vomiting, dizziness, semi-comatose state.
Sorrel (Rumex spp.)	Forb	All	Mild	Oxalic acid	Large quantities can cause interference with calcium metabolism in the body.
St. John's Wort or Goatweed, Klamath Weed (Hypericum perforatum)	Forb	All	Mild - Moderate	Hypericin	Photosensitization - blisters, swelling and lesions on the skin particularly light-skinned animals. Subsequent exposure has more severe symptoms. Loss of appetite, diarrhea, increased respiration and heartbeat, high temperature, blindness, convulsions, sometimes coma and death. Symptoms are often delayed.
Swamp Laurel (Kalmia sp.)	Shrub	Leaves, flowers	Mild - Moderate	Andromedotoxin, arbutin	Burning of lips, mouth, salivation, nausea, severe vomiting, coma and death in the most severe cases.
Tansy, Common (Tanacetum vulgare)	Forb	All	Moderate - Severe	Tanacetin	Rapid pulse, stomach inflammation, convulsions, abortion, occasionally fatal. However, rarely grazed because of strong taste and smell.
Tarweed (Amsinckia spp.)	Forb	All	Moderate, Cumulative	Pyrrolizidine	Liver lesions, enlarged liver, digestive disturbances, restlessness, lack of coordination, weakness, staggering, death. Liver damage is permanent. Usually only eaten in hay or when wilted. Drying or storage doesn't destroy toxins.
Vetch, Common (Vicia sativa)	Forb	Foliage, Seeds	Mild - Severe	Cyanogenic glycosides (produces cyanide)	Amount of toxins in plants highly variable. Initial rapid breathing followed by slow, difficult breathing, anxiety, excitement, confusion, headache, vomiting, dizziness, can cause death.
Yarrow (Achillea millefolium)	Forb	All	Mild	Glucosides and Alkaloids	If eaten in quantity, can cause gastric problems.
Yew (Taxus brevifolia)	Tree	All, except perhaps the flesh around the seed	Moderate - Severe	Alkaloid (taxine), ephedrine, cyanogenic glycoside	Gastroenteritis, nausea, vomiting, diarrhea, rash, drowsiness, irregular heartbeat, labored breathing, trembling, collapse. Large amounts can cause death.

** Many of these plants have similar effects on humans! The major symptoms and effects are listed, but the list is NOT all-inclusive. Consult the local Poison Control Center for a complete listing and information about treatment.

Compiled by: Marty Chaney, Pasture Management Specialist, USDA Natural Resources Conservation Service, Olympia, WA 12/99

Common Poisonous Plants of Western Washington Which Affect Livestock*