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Database of Toxic Plants in the United States

Below you will find the comprehensive list of toxic plants that has been compiled from many other sources.  They have been presorted in three ways: 1) alphabetically by common name, 2) alphabetically by scientific name, and 3) by growth type (browse, forb, grass, shrub, tree) and then alphabetically within each type by common name.

For the third option: browse means woody species generally smaller than shrubs; forbs are leafy species that may be either monocot or dicot, and may be annual, perennial, or biennial.

Last on the page you will find a listing of some common symptoms by toxin: these are notated in the database by 'See list for _____'.  The symptoms were simply too numerous to list within the database.  Bear in mind that your horse may or may not display all of the symptoms for any one toxin, depending upon the severity of the toxicity.

 

ALPHABETICALLY BY COMMON NAME

 

Common Name Scientific Name Area Affected Toxin (If Known) Type Comments; Regional Names
Acacia Acacia & Robinia spp. Gastric & Nervous Systems Glycosides; Phytotoxin Tree False acacia; black locust
Aconite Aconitum columbianum Gastric; Colic Alkaloid Aconitine Forb Monkshood; not toxic when dried; used in homeopathy
Akee Blighia sapida Teratogenic; Fetal Teratogens Tree  
Alsike clover Trifolium hybridum Liver Disease; Hepatitis; Teratogenic Mycotoxin Forb When wet/humid
American coffee berry Gymnocladius dioica Gastric; Diarrhea; Death Alkaloid Cytisine Tree Kentucky mahogany/coffee tree; nicker tree; stump tree
Anemone Ranunculus spp Colic/Diarrhea Glycosides; Protoanemonin Forb See buttercups; not toxic when dried
Arborvitae Thuja occidentalis Fetal Damage Thujone Tree Not common: toxic if consumed in quantity
Arrowgrass Triglochin maritimum Nervous; Respiratory; Death Cyanide; Prussic Acid Grass Also toxic when dried in hay.
Autumn crocus Colchicum autumnale Teratogenic; Fetal; Neurologic Teratogens Browse Meadow saffron
Avocado Persea americana Colic/Diarrhea; Mastitis; Cardiac; Death Persin Tree Guatemalan variety only; fruit/seeds/leaves
Azalea Rhododendron spp. Colic/Diarrhea; Tremors Cyanide; Ursol Acid Shrub Also toxic when dried; rhododendrons
Bastard toadflax Comandra pallida   Se Accumulator Forb  
Beardtongue Penstemon calycosus See List For Selenium Toxicosis Se Accumulator Forb  
Bermuda grass Cynodon dactylon Gastric System May have ergot Grass  
Be-still Thevetia thevetioides Colic/Diarrhea; Sudden Death Glycosides Tree Lucky nut tree; yellow oleander
Birdsville indigo Indigofera linnaei Photosensitization; Hepatotoxic Indospicine Forb  
Bishop's weed Ammi majus Photodermatitis Coumarin Forb Large bullwort
Bitter nightshade Solanum dulcamara Colic/Diarrhea Alkaloids; Solanine Forb European bittersweet; climbing nightshade
Bitter sneezeweed Helenium hoopesii GI Irritant Sesquiterpene Lactone Forb Sneezeweed
Bitterweed Hymenoxys odorata Mouth/GI Irritant Hymenoxen Forb  
Black henbane Hyoscyamus niger Convulsions; Coma; Death Glycoalkaloids Forb  
Black locust Robinia pseudoacacia Ataxia; Colic/Diarrhea; Paralysis Lectin Tree Bark is most toxic
Black nightshade Solanum nigrum Colic/Diarrhea Alkaloids; solanine Forb Deadly nightshade
Black walnut Juglans nigra Weakness; Laminitis; Dermatitis Unknown Tree  
Bladderpod Lesquerella gordonii Diarrhea; Weakness; Death Saponins Shrub  
Bleeding heart Dicentra spectabilis; formosa Convulsions; weakness; staggering Alkaloids; Isoquinoline Forb Dutchman's breeches
Bloodroot Sanguinaria canadensis Gastric; Muscular; Respiratory Alkaloids Forb  
Blue mustard Chorispora tenella Deformed Foals Glucosinolates Forb  
Bouncing Bet Saponaria officinalis Gastric/Diarrhea; Depression Saponin Forb Soapwort
Boxwood Buxus spp. Neurologic; Colic; Respiratory Cyclobuxin (Alkaloid) Shrub All plant parts toxic
Bracken fern Pteridium aquilinum  Thiamin Deficiency; Ataxia Thiaminase; Filicin Browse Western brackenfern; all parts poisonous
Bristlegrass Setaria spp Physical; Mouth/GI; Foam/Drool Physical Grass Green bristlegrass; hooked bristlegrass
Broom groundsel Senecio spartioides Hepatotoxic; Weakness Alkaloids Forb  
Broom snakeweed Gutierrezia sarothrae Se List; Abort/Repro Se Accumulator; Terpenes Shrub Turpentine weed; snakeweed; matchweed
Broomweed Gutierrezia microcephala Abortion; See List For Se Toxicosis Se Accumulator Forb  
Buckeye Aesculus hippocastanum Neurologic; Weakness; Trembling Saponin Tree All parts toxic; horse chestnut
Buckwheat Fagopyrum esculentum Photosensitization Fagopyrin Forb  
Budsage Artemesia spinescens Neurological Possibly monoterpenes Shrub  
Buffalo burr nightshade Solanum rostratum Colic/Diarrhea Alkaloids; Solanine Forb Buffalobur
Buffalobur Solanum rostratum Colic/Diarrhea Alkaloids; Solanine Forb Buffalo burr nightshade
Bull nettle Solanum carolinense Colic/Diarrhea Alkaloids; Solanine Forb  
Bull thistle Cirsium vulgare See List For Nitrate Toxicosis Nitrates Forb  
Burdock Arctium minus Mouth/GI Physical Forb  
Burr trefoil Medicago polymorpha Photosensitization From Liver Failure Mimosine Forb  
Burrow weed Haplopappus tenuisecta Neurological; Ataxia; Muscular Tremetol Forb Trembles
Butter and eggs Linarea vulgaris Gastric System Glycosides Forb Yellow toadflax
Buttercup Ranunculus spp Mouth/GI Irritant/Colic Protoanemonin (Alkaloid) Forb All buttercups; loss of milk production
Butterweed Senecio glabellus Hepatotoxic Alkaloids Forb  
Button bush Cephalanthus occidentalis Gastrointestinal Glycosides Shrub  
California buckeye Aesculus californica GI Irritant Saponin; Aesculen Tree New growth; leaves; nuts
Canada thistle Cirsium arvense See List For Nitrate Toxicosis Nitrates Forb  
Carolina jessamine Gelsemium sempervirens Gastric; Weakness; Respiratory Alkaloids Shrub Evening trumpetflower, false jessamine
Castor bean Ricinus communis Colic/Diarrhea; Ataxia Ricin (Toxalbumin); Lectin Forb Seeds in particular; highly toxic; see rosary pea
Cat's ears Hypochaeris radicata Possible stringhalt; Neurological Alkaloids Forb Flatweed, false dandelion
Cheatgrass Bromus tectorum Mouth/Digestive Tract Physical Grass Downy brome
Chinaberry Melia azedarach Gastric; Cardiac; Diarrhea Terpenes; unidentified Tree  
Chokecherry Prunus virginiana Sudden Death Cyanide/Glycosides Tree Drought & freeze increase toxicity
Christplant Euphorbia milii Skin Irritations; Mouth/GI Latex Shrub Crown of thorns
Clematis Clematis spp. Colic/Diarrhea; Neurotoxic Protoanemonin (Alkaloid) Browse All plant parts
Climbing bittersweet Celastrus scandens Neurological; Gastric Solanine Browse Nightshades
Climbing nightshade Solanum dulcamara Colic/Diarrhea Alkaloids; Solanine Forb European bittersweet; bitter nightshade
Clovers Trifolium spp Photosensitization; Hepatotoxic Slaframine Forb  
Cockle burrs Xanthium spp. Mouth/GI tract Physical Forb Cockleburs; 2 spp; seedlings/seeds toxic
Cockleburs Xanthium spp. Mouth/GI tract Physical Forb Cockle burrs; 2 spp; seedlings/seeds toxic
Cockspur Crataegus crus-galli Colic/Diarrhea Physical impaction Tree Hawthorn; cockspur hawthorn; fruits toxic
Coffee weed Cassia occidentalis Lameness; Muscle Weakness Anthraquinone Forb Sienna weed
Cohosh Actaea rubra Respiratory; Cardiac Glycoside Forb Red baneberry
Colorado rubberweed Hymenoxys richardsonii GI Irritant; Photosensitization Sesquiterpene  Forb Rubberweed; pingue
Comfrey Symphytum officinale Chronic Poisoning; Liver PA/Alkaloids Forb  
Common groundsel Senecio vulgaris See List For PA PA/Alkaloids Forb  
Common vetch Vicia sativa Blindness; Convulsions Cyanide; Neurotoxin Forb  
Copperweed Oxytenia acerosa GI Irritant; Weakness; Coma Possibly sesquiterpenes Shrub  
Corn cockle Agrostemma githago Muscles; ataxia Saponin Forb Seeds in particular
Corn lily Veratrum californicum Colic/Diarrhea; Teratogenic Steroid (Alkaloids) Forb Western false hellebore; false hellebore; chasing green
Creeping charlie Glechoma hederacea Respiratory; Sweating Glechomin Forb Ground ivy; all parts when fresh; not in stored hay
Creeping/trailing indigo Indigofera spicata Teratogenic; Ataxia; Hepatotoxic Indospicine Forb Picas
Crofton weed Ageratina adenophora Ataxia; Muscular Tremetol Forb Eupatorium adenophorum
Crown of thorns Euphorbia milii Skin Irritations; Mouth/GI Latex Shrub Christplant
Crown vetch Coronella varia Weight loss; Abnormal behavior Neurotoxin Forb  
Curly dock Rumex crispus Kidney; Tremors; Coma; Death Oxalates Forb  
Curlycup gumweed Grindelia squarrosa See List For Selenium Toxicosis Se Accumulator Forb Resinweed; gumweed
Cutleaf nightshade Solanum Colic/Diarrhea Alkaloids/Glycosides Forb  
Daffodil Narcissus spp. Gastric/mouth, Dermatitis Alkaloids; Narcissine Forb Bulbs in particular; narcissus
Deadly nightshade Solanum nigrum Colic/Diarrhea; Collapse Alkaloids/Solanine Forb Black nightshade; drought increases toxicity
Deathcamas Zigadenus spp Neurotoxin; Colic; Death Alkaloids Forb 15 spp deadly within days; 8-10 lbs
Delphinium  Delphinium spp Paralysis; Respiratory Aconitin (Alkaloid); Nitrates Forb Larkspur
Dogbane Apocynum cannabinum Cardiac; Sudden Death Cardiac Glycosides Forb Hemp dogbane; Indian hemp; under 24 hours
Downy brome Bromus tectorum Mouth/Digestive Tract Physical Grass Cheatgrass
Dutchman's breeches Dicentra cucullaria Trembling; Diarrhea; Convulsions Alkaloids Forb Squirrel corn; bleeding heart family
Easter lily Lilium longiflorum Kidney; Gastric; Weakness Unidentified Forb  
Elderberry Sambucus canadensis Cardiac/Sudden Death; Ataxia Nitrates; Glycosides Tree See list for nitrate toxicosis; death within minutes
English ivy Hedera helix Gastric; Respiratory; Coma; Death Saponin Browse Entire plant
European bittersweet Solanum dulcamara Colic/Diarrhea Alkaloids Forb Bitter nightshade; climbing nightshade
European hemlock Conium maculatum Death; Teratogenic Teratogens; Alkaloids Forb Spotted/poison hemlocks; 2-3 hours
European milkvetch Astragalus spp Fetal Damage Teratogens Forb  
Evening trumpetflower Gelsemium sempervirens Gastric; Weakness; Respiratory Alkaloids Shrub Carolina jessamine, false jessamine
False dandelion Hypochaeris radicata Lameness Alkaloids Forb Cat's ears, flatweed
False hellebore Veratrum californicum Colic/Diarrhea; Teratogenic Steroid (Alkaloids) Forb Western false hellebore; corn lily; chasing green
Fetterbush Pieris spp. Colic/Diarrhea Arbutin Shrub  
Fiddleneck Amsinckia menziesii Hepatotoxic; Weight Loss PA; Nitrates Forb Tarweed; see list for nitrate toxicosis
Field bindweed Convolvulus arvensis Colic/Diarrhea; Cardiac Alkaloids; Nitrates Forb Morning glory; see list for nitrate toxicosis
Field mustard Brassica rapa Gastric/Diarrhea; Anorexia Glucosinolates Forb  
Fireweed Kochia scoparia Photosensitization; Hepatotoxic; Nitrate Oxalates; Nitrates Forb Kochia; summer cypress
Flatweed Hypochaeris radicata Lameness Alkaloids Forb Cat's ears, false dandelion
Flixweed Descurainia sophia Deformed Foals Teratogens Forb Sophia, tansy mustard
Foxglove Digitalis purpurea Cardiac; Gastric; Sudden Death Glycosides; saponins Forb Purple Foxglove; under 24 hours
Foxtail barley Hordeum jubatum Mouth/GI Physical Grass  
Freckled milkvetch Astragalus lentiginosus Neurological Neurotoxin Forb  
Fringed sage Artemisia frigida Neurological Neurotoxin Shrub Prairie sagewort
Fumewort Corydalis spp. Convulsions; Staggers; Collapse Alkaloids Forb Several species are included.
Gambel's oak Quercus gambelii Colic/Diarrhea Tannic Acid; Gallotannins Tree Tannins in young leaves; bark; acorns
German millet Setaria italica Kidney; Joint; Bone   Grass Crop/pasture grass
Golden chain tree Laburnum anagryroides GI; Neuromuscular Alkaloids; Cytisine Tree Entire plant; seeds in particular
Golden oatgrass Trisetum flavescens Weakness; Weight loss; Calcinosis Unknown Grass  
Golden weed Haplopappus engelmannii See List For Selenium Toxicosis Selenium Shrub  
Goldenrods Solidago spp See List For Nitrate Toxicosis Nitrates Forb  
Goose grass Triglochin spp. Ataxia; Death Cyanogenic Glycosides Grass Arrow/pod grasses; within minutes
Goosegrass Eleusine indica Gastric Distress Alkaloids Grass Wiregrass
Greasewood Sarcobatus vermiculatus Ca Deficiency; Colic/Diarrhea Oxalates Shrub  
Green bristlegrass Setaria spp Mouth/Throat/Gastric Physical Grass Bristlegrass; hooked bristlegrass
Green false hellebore Veratrum eschscholtzii Fetal Damage; Colic/Diarrhea Protoanemonin; Alkaloids Forb Cyclops foals
Ground ivy Glechoma hederacea Respiratory; Sweating Glechomin Forb Creeping charlie; all parts when fresh; not in stored hay
Groundsel Senecio plattensis Hepatotoxic; Teratogenic; Weakness PA; Teratogens Forb Ragwort.
Gumweed Grindelia squarrosa See List For Selenium Toxicosis Se Accumulator Shrub Curlycup gumweed; resinweed
Hairy nightshade Solanum sarrachoides Colic/Diarrhea Alkaloids Forb  
Halogeton Halogeton glomeratus Kidney; Colic/Diarrhea Oxalates Forb  
Hard maple Acer spp. Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Hawthorn Crataegus crusgalli Colic/Diarrhea; Impaction Physical Tree Cockspur; fruits
Heliotrope Heliotropium arborescens Weight Loss; hepatotoxic Pyrrolizidin Forb Seeds in particular
Hemp Cannabis sativa Neurotoxin 60 Compounds Forb Marijuana
Hemp dogbane Apocynum cannabinum Cardiac; Sudden Death Cardiac/Cyanogenic Glycosides Forb Dogbane; Indian hemp; all parts toxic
Hoary alyssum Berteroa incana GI; Founder; Laminitis; Edema Unknown Forb  
Honeysuckle Ionicera periclymenum Diarrhea; Lethargy   Shrub Plants and berries
Honey mesquite Prosopis glandulosa Colic/Diarrhea; Impaction Physical Tree Fruits only; mesquite
Hooked bristlegrass Setaria spp Mouth/Throat/Gastric Physical Grass Green bristlegrass; bristlegrass
Horse chestnut Aesculus hippocastanum Muscles; Ataxia Saponin; Aesculen Tree All parts toxic; buckeye
Horse nettle Solanum carolinense Colic/Diarrhea; Paralysis; Death Alkaloids Forb Nightshades
Horsetails Equisetum spp. Weakness; Stumbling; Arrhythmia Aconitic Acid Forb Snakegrass; scouring rush; all parts toxic; B1 may help
Houndstongue Cynoglossum officinale Liver; Weight Loss Hepatotoxin/PA Forb All stages of plant; liver failure
Hyacinth Hyacinthus orientalis Diarrhea; Colic Alkaloids Forb Garden hyacinth; foliage may cause dermatitis
Hydrangea Hydrangea spp. Gastric/Diarrhea; Respiratory Cyanogenic Glycosides Shrub Several spp; entire plant toxic
Indian hemp Apocynum cannabinum Cardiac; Sudden Death; Colic Cardiac Glycosides Forb Dogbane; hemp dogbane; under 24 hours
Indian paintbrush Castilleja linariaefolia See List For Selenium Toxicosis Se Accumulator Forb  
Ironweed Sideranthus grindelioides See List For Selenium Toxicosis Se Accumulator Shrub  
Jack-in-the-Pulpit Arisaema triphyllum Lips/Mouth/Tongue; Salivation Oxalates Forb Several spp.
Jamestown weed Datura stramonium Cardiac; Coma; Death Hyoscyamine (Alkaloid) Forb Stinkweed; mad apple; jimson weed; thornapple
Japanese yew Taxus cuspidata Cardiac; Sudden Death Taxine (Alkaloid) Shrub All parts except berries; death within hours
Jerusalem cherry Solanum pseudocapsicum Colic/Diarrhea; See Nitrate List Alkaloids; Nitrates Shrub  
Jessamine, day blooming Cestrum diurnum Calcinosis; Lameness/Weakness Hyoscine Tree Wild jasmine
Jessamine, false Gelsemium sempervirens Gastric; Weakness; Respiratory Alkaloids Shrub  
Jessamine, night blooming Cestrum nocturnum Lameness/Muscle Weakness Atropine-like Alkaloids Tree  
Jimmy weed Haplopappus heterophyllus Neurological; Muscle; Ataxia Tremetol Shrub Southern goldenbush; trembles
Jimson weed Datura stramonium Teratogenic; Neurological; See Nitrates Alkaloids; Nitrates Forb Stinkweed; mad apple; jamestown weed; thornapple
Johnsongrass Sorghum halepense Ataxia; Cardiac Cyanogenic Glycosides Grass Within minutes
Kentucky coffee tree Gymnocladius dioica Gastric/Diarrhea, Respiratory Cytosine Tree Kentucky mahogany, nicker, stump, American coffee tree
Kentucky mahogany tree Gymnocladius dioica Gastric/Diarrhea, Respiratory Cytosine Tree Kentucky/American coffee tree; nicker tree; stump tree
Klamath weed Hypericum perforatum Skin; Photosensitize Naphthodianthron; Hypericin Forb St. Johnswort; goatweed?
Kleingrass Panicum coloratum Liver Disease; Hepatitis Mycotoxin Grass Wet/humid conditions; not in hay; dew poisoning
Kochia Kochia scoparia Photosensitization; Hepatotoxic; Nitrate Oxalates; Nitrates Forb Fireweed, summer cypress 
Lamb's tongue groundsel Senecio integerrimus Hepatotoxic PA Forb  
Lambsquarters Chenopodium album See List For Nitrate Toxicosis Nitrates Forb  
Lantana Lantana camara Liver damage; depression; neurological Lantadene Shrub Several spp.; entire plant
Large bullwort Ammi majus Photodermatitis Coumarin Forb Bishop's weed
Larkspur Delphinium spp Colic; Respiratory Paralysis; Death Aconitin; Esters; Nitrates Forb Delphinium; poison weed; 80 spp?; young plants especially
Laurel Kalmia spp. Colic/Diarrhea; Depression; Ataxia Alkaloids; Arbutin Shrub Several spp.; leaves especially toxic
Leafy spurge Euphorbia esula Photosensitivity; Colic/Diarrhea Latex Forb Especially light-colored horses
Lily of the valley Convallaria majalis Sudden Death; Cardiac; Gastric Glycosides Forb Under 24 hours
Littleleaf horsebrush Tetradymia glabrata Hepatotoxic Alkaloids Shrub  
Locoweed Astragalus; Oxytropis spp Neurological; Teratogen; Wasting Alkaloids; Swainsonine Forb Early spring emergence; addictive; equines susceptible
Longspine sandbur Cenchrus longispinus Mouth/GI Physical Forb Sandbur
Lucky nut tree Thevetia thevetiodes Colic/Diarrhea; Sudden Death Glycosides Tree Be-still; yellow oleander
Lupine Lupinus spp Teratogenic; Fetal Alkaloids; Slaframine Forb Young & bolting more toxic
Mad apple Datura stramonium Cardiac; Coma; Death Hyoscyamine (Alkaloid) Forb Stinkweed; jimsonweed; Jamestown weed; thornapple
Maleberry Lyonia ligustrina Colic/Diarrhea; Ataxia; Depression Arbutin Shrub  
Mallows Malvaceae spp See List For Nitrate Toxicosis Nitrates Forb Several spp.
Marestail Equisetum spp Neurological Thiaminase; Neurotoxin Forb  
Marijuana Cannabis sativa Neurotoxin 60 Compounds; THC Forb Hemp  
Marsh marigold Caltha palustris GI Irritant; Colic/Diarrhea Protoanemonin Forb  
Matchweed Gutierrezia sarothrae See List For Selenium Toxicosis Se Accumulator Shrub Broomweed; turpentine weed; snakeweed; broom snakeweed
Mayapple Podophyllum peltatum Gastric/Diarrhea, Respiratory; Neuro Podophyllotoxin Forb  
Meadow saffron Colchicum autumnale Teratogenic; Fetal Teratogens Forb Autumn crocus
Medusahead rye Taentherum asperum Mouth/GI Physical Grass  
Mesquite Prosopis glandulosa Colic/Diarrhea; Impaction Physical Impaction Tree Fruits only; honey mesquite
Milkvetch Astragalus spp Teratogenic; ataxia; neuro; weakness Neurotoxin; Se Forb Hoof abnormalities; wasting disease; several spp.
Milkweeds Asclepias spp Cardiac; Sudden Death; Colic Glycosides Forb Under 24 hours; several spp.
Mistletoe Phoradendron & Viscum spp. Colic, Diarrhea, Sudden Death Glycoproteins Shrub Several spp.
Monkshood Aconitum columbianum See Nitrate List; Gastric; Neurological Nitrates; Alkaloids Forb Aconite
Morning glory Convolvulus arvensis Colic/Diarrhea; Cardiac Alkaloids; Nitrates Forb Field bindweed
Mountain laurel Kalmia latifolia Colic/Diarrhea; Cardiac Andromedotoxin Shrub  
Mountain mahogany Cercocarpus spp. Cardiac Cyanide Tree  
Mountain fetterbush Pieris spp. Colic/Diarrhea Acetylandromedol; Grayanotoxins Shrub Needles in particular
Narcissus Narcissus spp. Gastric/mouth, Dermatitis Alkaloids; Narcissine Forb Daffodils
Needlegrass Stipa spp Mouth/Gastric System Physical Grass  
Nicker tree Gymnocladius dioica Gastric/Diarrhea, Respiratory Cytosine Tree Kentucky coffee/mahogany, American coffee, stump trees
Oak Quercus breviloba Colic/Diarrhea Tannic Acid/Gallotannins Tree Young leaves; bark; acorns; seasonal; picas
Ohio buckeye Aesculus glabra GI Irritant, Hemolysis Aesculin Tree New growth; leaves; nuts
Oleander Nerium oleander Sudden Cardiac Death; Colic/Diarrhea Cardiac Glycosides Shrub Highly toxic
Onion, domestic Allium spp Anemia; Weakness Alcylsulfides; Disulfides Forb In large quantities
Perennial ryegrass Lolium perenne Skin; Photosensitize Photosensitizing Agent Grass  
Periwinkle Vinca rosea Teratogenic Teratogens Shrub  
Persimmon Diospyros virginiana Colic/Diarrhea; Impaction Physical Tree Fruits only
Philodendron Philodendron spp Mouth, GI Tract, Respiratory, Death Oxalates Browse  
Pigweed Amaranthus retroflexus See Lists for Nitrate Toxicosis Nitrates; Oxalates Forb Redroot pigweed; drought increases toxicity; oxalate list?
Pincherry Prunus pensylvanica Sudden Death Cyanogenic Glycosides Tree Drought increases toxicity
Pingue Hymenoxys richardsonii GI Irritant; Photosensitization Sesquiterpene  Forb Colorado rubberweed; rubberweed; bitterweed
Poinsettia Euphorbia pulcherrima Gastric; Dermatitis; See Nitrate List Latex, Euphorbin, Nitrates Shrub  
Poison hemlock Conium maculatum Death; Teratogenic Alkaloids Forb All parts toxic; not in hay; chasing green in spring; 2-3 hours
Poison ivy Toxicodendron radicans Gastrointestinal, Dermatitis Urushiol, Catechols Forb  
Pokeweed Phytolacca americana Colic/Diarrhea Phytolaccatoxin Forb Entire plant toxic
Ponderosa pine Pinus ponderosa Abortive Isocuppressic acid Tree  
Poppies Papaver spp. Teratogenic Teratogens Forb  
Porcupine grass Miscanthus sinensis Mouth/GI tract Physical Grass  
Potato Solanum tuberosum Colic/Diarrhea; Weakness Alkaloids; Solanine Forb  
Prairie sagewort Artemisia frigida Neurological Neurotoxin Shrub Fringed sage
Prairie three-awn Aristida oligantha Mouth/GI Physical Grass  
Prickly pear Opuntia spp. Mouth/GI Physical Shrub  
Prince's plume Stanleya pinnata See List For Selenium Toxicosis Selenium Shrub  
Privets Ligustrum vulgare Colic/Diarrhea Glycosides; Iridoid Shrub Entire plant
Puncture vine Tribulus terrestris Mouth/GI tract Physical Forb  
Purple foxglove Digitalis purpurea Cardiac; Sudden Death Cyanogenic Glycosides Forb Foxglove
Purple locoweed Oxytropis lambertii Neurological; Teratogen; Wasting Alkaloids; Swainsonine Forb Early spring emergence; addictive; equines susceptible
Purple mint Perilla frutescens Respiratory  Ketones Forb  
Ragweed Ambrosia artemesiafolia See List For Nitrate Toxicosis Nitrates Forb  
Rattlebox Crotalaria spp Weight loss; hepatotoxic; chronic PA Shrub Rattlepod
Rattlepod Crotalaria spp Weight loss; hepatotoxic; chronic PA Shrub Rattlebox
Red baneberry Actaea rubra Respiratory; Cardiac Glycoside Forb Cohosh
Red buckeye Aesculus pavia GI Irritant; Muscle Weakness; Coma Glycosides Tree New growth; leaves; nuts
Red clover Trifolium pratense Skin; Liver Mycotoxin Forb  
Red maple Acer rubrum Anemia; Arrythmia; Weakness Unknown Oxidant Tree Red X silver hybrids may be toxic; small amounts; dried only
Redroot pigweed Amaranthus spp See Lists for Nitrate Toxicosis Nitrates; Oxalates Forb Pigweed; drought increases toxicity; oxalate list?
Reed canarygrass Phalaris arundinacea Muscular Weakness; Collapse Alkaloids Grass  
Resinweed Grindelia squarrosa See List For Selenium Toxicosis Selenium Shrub Curlycup gumweed
Rhododendron Rhododendron spp. Colic/Diarrhea; Tremors; Respiratory Cyanide; Ursol Acid Shrub Also toxic when dried; azalea.
Rhubarb Rheum rhaponticum Gastrointestinal; Cardiovascular Oxalates Forb Leaves
Richweed Ageratina altissima Muscular; Ataxia; Swallowing Tremetol Forb White snakeroot
Riddell's ragwort Senecio riddellii Hepatotoxic; Weakness; Chronic PA Forb  
Rock maple Acer spp. Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Rosary pea Abrus precatorius Colic/Diarrhea; Ataxia Lectin Browse See castor bean
Rubberweed Hymenoxys richardsonii GI Irritant; Photosensitization Sesquiterpene  Forb Colorado rubberweed; pingue
Russian knapweed Acroptilon repens Chewing Disease Sesquiterpene; Another Unknown Forb Same toxin as starthistle; no cure/recovery
Russian thistle Salsola iberica See List For Nitrate Toxicosis Nitrates Forb  
Sagebrush Artemesia spp Neurological Monoterpenes Forb  
Saltbush Atriplex spp See List For Selenium Toxicosis Selenium Forb  
Sand sage Artemesia filifolia Neurological; Ataxia Volatile Oils Forb Sage sickness
Sandbur Cenchrus longispinus Mouth/GI Physical Forb Longspine sandbur
Scarlet pimpernel Anagallis arvensis Mouth; Staggering; Ataxia Terpenoid; Glycoside Forb  
Scotchbroom Cytisus scoparius Gastrointestinal; Hepatotoxic Alkaloids Shrub Entire plant
Scouring rush Equisetum arvense Neurological; Ataxia; Blindness Alkaloids; Thiaminase Forb Horsetails; snakegrass; all parts toxic; B1 may help
Sienna weed Cassia occidentalis Colic/Diarrhea; Ataxia; Weakness Anthraquinone Forb Coffee weed
Sensitive fern Onoclea sensibilis Neurological; Ataxia Thiaminase Forb  
Service berry Amelanchier alnifolia Death; Ataxia; Heart Cyanogenic Glycosides Tree Death within minutes is possible
Shamrock Oxalis spp KIdney; Diarrhea/Colic Oxalates Forb  
Shepherd's purse Capsella bursa-pastoris Teratogenic Teratogens Forb Deformed foals
Shinnery oak Quercus havardii Colic/Diarrhea Tannic Acid Tree Shin oak; tannins in young leaves; bark; acorns
Silver maple Acer spp. Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Silverleaf nightshade Solanum elaeagnifolium Colic/Diarrhea Alkaloids; Solanine Forb  
Skunk cabbage Symplocarpus foetidus Cardiovascular; Shock Alkaloids Forb  
Smartweed Polygonum spp See List For Nitrate Toxicosis Nitrates; Saponin Forb Entire plant
Snakegrass Equisetum arvense; spp Ataxia; Neurological; Blindness Alkaloids; Thiaminase Forb Horsetails; scouring rush; all parts toxic; B1 may help
Snakeweed Gutierrezia sarothrae See List For Selenium Toxicosis Selenium Shrub Turpentine weed; broom snakeweed; matchweed
Sneezeweed Helenium hoopesii GI Irritant Sesquiterpene Lactone Forb Bitter sneezeweed
Snow on the mountain Euphorbia marginata Mouth/GI; Diarrhea Esters Forb  
Soapwort Saponaria officinalis Gastric/Diarrhea; Depression Saponin Forb Bouncing Bet
Soft maple Acer spp. Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Sophia Descurainia sophia Deformed Foals Teratogens Forb Flixweed, tansy mustard
Sorghum Sorghum spp. Cardiac; See List For Nitrate Toxicosis Cyanogenic Glycosides; Nitrates Grass 20 spp.; when stressed/drought; sudan grass
Sorrel Oxalis & Rumes spp. Kidney; Colic/Diarrhea Oxalates Forb  
Soursob Oxalis spp Kidney; Colic/Diarrhea Oxalates Forb  
Southern goldenbush Haplopappus heterophyllus Neurological; Muscle; Ataxia Tremetol Shrub Jimmy weed; trembles
Spineless horsebrush Tetradymia canescens Hepatotoxic Alkaloids Shrub  
Spiny cocklebur Xanthium spinosum Mouth/GI, Hepatotoxic Glycosides; Physical Forb  
Spotted cowbane Pastinaca sativa Colic/Diarrhea; Photodermatitis Coumarin Forb Wild parsnip
Spotted locoweed Astragalus spp Teratogenic; Neurological; Death Swainsonine Forb  
Spring parsley Cymopterus watsonii Skin; Photosensitize Coumarin Forb Photodermatitis
Squirrel corn Dicentra cucullaria Trembling; Diarrhea; Convulsions Alkaloids Forb Dutchman's breeches; bleeding heart family
Squirreltail Sitanion hystrix Mouth/GI Physical Grass Elymus elymoides
St. Johnswort Hypericum perforatum Skin; Photosensitize Naphthodianthron; Hypericin Forb Klamath weed; entire skin loss
Staggergrass Amanthium muscaetoxicum Respiratory; Weakness; Death Alkaloids Grass  
Star of Bethlehem Ornithogalum umbellatum Gastric/Diarrhea; Depression Saponin Forb Entire plant
Stickseed Hackelia & Trichodesma spp. Weight Loss; Hepatotoxic; Chronic PA Forb  
Stinging nettle Urtica dioica Mouth/GI; See List For Nitrate Toxicosis Physical; Nitrates Forb  
Stinkweed Datura stramonium Teratogenic; Cardiac; Death Hyoscyamine (Alkaloid) Forb Jimsonweed; mad apple; jamestown weed; thornapple
Stump tree Gymnocladius dioica Gastric/Diarrhea, Respiratory Cytosine Tree Kentucky mahogany/coffee, American coffee, nicker trees
Sudan grass Sorghum bicolor Death; Ataxia; Teratogenic; Paralysis Cyanogenic Glycosides Grass Drought & freeze increase toxicity
Sugar maple Acer spp. Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Summer cypress Kochia scoparia Photosensitization; Hepatotoxic; Nitrate Oxalates; Nitrates Forb Fireweed; kochia
Summer pheasant's eye Adonis aestivalis Cardiac; Colic Adonidine Forb  
Sweet bubby Calycanthus floridus Tetany; Convulsions; Neurological Calycanthin; Alkaloids Shrub Sweet shrub
Sweetshrub Calycanthus floridus Tetany; Convulsions; Neurological Calycanthin; Alkaloids Shrub Sweet bubby
Tall big sagebrush Artemisia tridentata Neurologic Volatile Oils Shrub  
Tall fescue Festuca arundinacea Abortion; Malformed Fetus Endophytic Fungus; Alkaloids Grass  
Tanglehead Heteropogon contortus Mouth/GI Physical Grass  
Tansy mustard Descurainia sophia Deformed Foals Teratogens Forb Flixweed, sophia
Tansy ragwort Senecio jacobaea Hepatotoxic; Neurological PA Forb Maintains toxicity in hay; equines highly susceptible
Tarweed Amsinckia intermedia Hepatotoxic; Weight Loss PA Forb Fiddleneck
Thornapple Datura stramonium Teratogenic Hyoscyamine (Alkaloid) Forb Jimson weed; Jamestown weed; stinkweed; mad apple
Threadleaf groundsel Senecio douglasii Hepatotoxic; Weakness PA Shrub Woolly groundsel
Three-awn grasses Aristida spp. Mouth/GI Physical Grass  
Tobacco Nicotiana glauca Teratogenic Teratogens Forb  
Tomato Lycopersicon spp. Colic/Diarrhea; Weakness Hyoscine Forb  
Tulip Tulipia spp Dermatitis; Weakness; Respiratory Tuliposide Forb  
Tumble mustard Sysymbrium altissimum Teratogenic Teratogens Forb  
Turpentine weed Gutierrezia sarothrae See List For Selenium Toxicosis Selenium Shrub Broom snakeweed; snakeweed; matchweed
Two-grooved milkvetch Astragalus bisculatus See List For Selenium Toxicosis Selenium Forb Freeze
Viper's bugloss Echium vulgare Liver Fibrosis/Failure PA Forb Seeds in particular
Water hemlock Cicuta douglasii Tremors; Convulsions; Death Cicutoxin Forb Western water hemlock; single mouthful; death in minutes
Western brackenfern Pteridium aquilinum Thiamin Deficiency Thiaminase; Filicin Browse Bracken fern; all parts poisonous
Western chokecherry Prunus spp Sudden Death Cyanogenic Glycosides Tree  
Western false hellebore Veratrum californicum Fetal Damage Steroid (Alkaloids) Forb False hellebore; corn lily
Western water hemlock Cicuta douglasii Tremors; Convulsions/ Death Cicutoxin Forb Water hemlock; single mouthful; death in minutes
White bryony Bryonia cretica Sweating; Diuresis; Convulsions Lectine; Polyhydroxic Acids Browse Berries; sap; roots; worse when dried
White locoweed Oxytropis sericea Neurological; Teratogen; Wasting Alkaloids; Swainsonine Forb Early spring emergence; addictive; equines susceptible
White maple Acer spp. Possibly Anemia Unknown Oxidant Tree  
White prairie aster Aster falcatus See List For Selenium Toxicosis Selenium Forb  
White snakeroot Ageratina altissima Muscular; Ataxia; Swallowing Tremetol Forb Richweed
White sweet clover Melilotus alba Anemia; Hemorrhage; Weakness Prussic Acid; Dicoumarol Forb When spoiled; in haylage
Wild blue flax Linum lewisii Ataxia; Cardiac Glycosides Forb Death may occur within minutes
Wild cherry Prunus serotina Sudden Death Cyanogenic Glycosides Tree  
Wild iris Iris missouriensis GI Irritant; Diarrhea; Dermatitis Irisine Forb New growth; leaves; nuts
Wild jasmine Cestrum diurnum Calcinosis; Lameness/Weakness Hyoscine Tree Jessamines
Wild mustard Sinapis arvensis Salivation; Collapse; Death Glucosinolates Forb  
Wild oat grass Avena fatua See List For Nitrate Toxicosis Nitrates Grass Wild oats
Wild onion Allium spp Anemia; Weakness Alcylsulfides; Disulfides Forb  
Wild parsnip Pastinaca sativa Colic/Diarrhea; Photodermatitis Coumarin Forb Spotted cowbane
Wild pea Lathyrus latifolius Teratogenic Teratogens Browse  
Wild tree tobacco Nicotiana glauca Fetal Damage Teratogens Tree  
Wiregrass Eleusine indica Gastric Distress Alkaloids Grass Goosegrass
Woody aster Xylorhiza glabriscula See List For Selenium Toxicosis Selenium Shrub  
Woolly groundsel Senecio douglasii Hepatotoxic; Weakness; Chronic PA Shrub Threadleaf groundsel
Woolly locoweed Astragalus mollismus Neurological; Teratogen; Wasting Alkaloids; Swainsonine Forb Early spring emergence; addictive; equines susceptible
Yellow bristlegrass Setaria pumila Mouth/GI; Foam/Drool Physical Grass  
Yellow buckeye Aesculus octandra GI Irritant; Hemolysis Aesculin Tree  
Yellow oleander Thevetia peruviana Colic/Diarrhea; Sudden Death Glycosides Shrub Be-still; lucky nut tree
Yellow starthistle Centaurea solstitialis Chewing Disease Alkaloids; Sesquiterpenes Forb Russian knapweed; no recovery; addictive
Yellow sweet clover Melilotus officinalis Anemia; Hemorrhage; Weakness Dicoumarol Forb Only when spoiled and in haylage
Yellow toadflax Linarea vulgaris Gastric System Glycosides Forb Butter and eggs
Yew Taxus spp Sudden Death; Neurological; Cardiac Taxin (Alkaloid); Cyanogens Shrub All parts except berries; single mouthful deadly; within hours

 

ALPHABETICALLY BY SCIENTIFIC NAME

 

Scientific Name Common Name Area Affected Toxin (If Known) Type Comments; Regional Names
Abrus precatorius Rosary pea Colic/Diarrhea; Ataxia Lectin Browse See castor bean
Acacia & Robinia spp. Acacia Gastric & Nervous Systems Glycosides; Phytotoxin Tree False acacia; black locust
Acer rubrum Red maple Anemia; Arrythmia; Weakness Unknown Oxidant Tree Red X silver hybrids may be toxic; small amounts; dried only
Acer spp. Hard maple Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Acer spp. Rock maple Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Acer spp. Silver maple Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Acer spp. Soft maple Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Acer spp. Sugar maple Possibly Anemia Unknown Oxidant Tree Possibly toxic, as with other maple spp.
Acer spp. White maple Possibly Anemia Unknown Oxidant Tree  
Aconitum columbianum Aconite Gastric; Colic Alkaloid Aconitine Forb Monkshood; not toxic when dried; used in homeopathy
Aconitum columbianum Monkshood See Nitrate List; Gastric; Neurological Nitrates; Alkaloids Forb Aconite
Acroptilon repens Russian knapweed Chewing Disease Sesquiterpene; Another Unknown Forb Same toxin as starthistle; no cure/recovery
Actaea rubra Cohosh Respiratory; Cardiac Glycoside Forb Red baneberry
Actaea rubra Red baneberry Respiratory; Cardiac Glycoside Forb Cohosh
Adonis aestivalis Summer pheasant's eye Cardiac; Colic Adonidine Forb  
Aesculus californica California buckeye GI Irritant Saponin; Aesculen Tree New growth; leaves; nuts
Aesculus glabra Ohio buckeye GI Irritant, Hemolysis Aesculin Tree New growth; leaves; nuts
Aesculus hippocastanum Buckeye Neurologic; Weakness; Trembling Saponin Tree All parts toxic; horse chestnut
Aesculus hippocastanum Horse chestnut Muscles; Ataxia Saponin; Aesculen Tree All parts toxic; buckeye
Aesculus octandra Yellow buckeye GI Irritant; Hemolysis Aesculin Tree  
Aesculus pavia Red buckeye GI Irritant; Muscle Weakness; Coma Glycosides Tree New growth; leaves; nuts
Ageratina adenophora Crofton weed Ataxia; Muscular Tremetol Forb Eupatorium adenophorum
Ageratina altissima Richweed Muscular; Ataxia; Swallowing Tremetol Forb White snakeroot
Ageratina altissima White snakeroot Muscular; Ataxia; Swallowing Tremetol Forb Richweed
Agrostemma githago Corn cockle Muscles; ataxia Saponin Forb Seeds in particular
Allium spp Onion, domestic Anemia; Weakness Alcylsulfides; Disulfides Forb In large quantities
Allium spp Wild onion Anemia; Weakness Alcylsulfides; Disulfides Forb  
Amanthium muscaetoxicum Staggergrass Respiratory; Weakness; Death Alkaloids Grass  
Amaranthus retroflexus Pigweed See Lists for Nitrate Toxicosis Nitrates; Oxalates Forb Redroot pigweed; drought increases toxicity; oxalate list?
Amaranthus spp Redroot pigweed See Lists for Nitrate Toxicosis Nitrates; Oxalates Forb Pigweed; drought increases toxicity; oxalate list?
Ambrosia artemesiafolia Ragweed See List For Nitrate Toxicosis Nitrates Forb  
Amelanchier alnifolia Service berry Death; Ataxia; Heart Cyanogenic Glycosides Tree Death within minutes is possible
Ammi majus Bishop's weed Photodermatitis Coumarin Forb Large bullwort
Ammi majus Large bullwort Photodermatitis Coumarin Forb Bishop's weed
Amsinckia intermedia Tarweed Hepatotoxic; Weight Loss PA Forb Fiddleneck
Amsinckia menziesii Fiddleneck Hepatotoxic; Weight Loss PA; Nitrates Forb Tarweed; see list for nitrate toxicosis
Anagallis arvensis Scarlet pimpernel Mouth; Staggering; Ataxia Terpenoid; Glycoside Forb  
Apocynum cannabinum Dogbane Cardiac; Sudden Death Cardiac Glycosides Forb Hemp dogbane; Indian hemp; under 24 hours
Apocynum cannabinum Hemp dogbane Cardiac; Sudden Death Cardiac/Cyanogenic Glycosides Forb Dogbane; Indian hemp; all parts toxic
Apocynum cannabinum Indian hemp Cardiac; Sudden Death; Colic Cardiac Glycosides Forb Dogbane; hemp dogbane; under 24 hours
Arctium minus Burdock Mouth/GI Physical Forb  
Arisaema triphyllum Jack-in-the-Pulpit Lips/Mouth/Tongue; Salivation Oxalates Forb Several spp.
Aristida oligantha Prairie three-awn Mouth/GI Physical Grass  
Aristida spp. Three-awn grasses Mouth/GI Physical Grass  
Artemesia filifolia Sand sage Neurological; Ataxia Volatile Oils Forb Sage sickness
Artemesia spinescens Budsage Neurological Possibly monoterpenes Shrub  
Artemesia spp Sagebrush Neurological Monoterpenes Forb  
Artemisia frigida Fringed sage Neurological Neurotoxin Shrub Prairie sagewort
Artemisia frigida Prairie sagewort Neurological Neurotoxin Shrub Fringed sage
Artemisia tridentata Tall big sagebrush Neurologic Volatile Oils Shrub  
Asclepias spp Milkweeds Cardiac; Sudden Death; Colic Glycosides Forb Under 24 hours; several spp.
Aster falcatus White prairie aster See List For Selenium Toxicosis Selenium Forb  
Astragalus bisculatus Two-grooved milkvetch See List For Selenium Toxicosis Selenium Forb Freeze
Astragalus lentiginosus Freckled milkvetch Neurological Neurotoxin Forb  
Astragalus mollismus Woolly locoweed Neurological; Teratogen; Wasting Alkaloids; Swainsonine Forb Early spring emergence; addictive; equines susceptible
Astragalus spp European milkvetch Fetal Damage Teratogens Forb  
Astragalus spp Milkvetch Teratogenic; ataxia; neuro; weakness Neurotoxin; Se Forb Hoof abnormalities; wasting disease; several spp.
Astragalus spp Spotted locoweed Teratogenic; Neurological; Death Swainsonine Forb  
Astragalus; Oxytropis spp Locoweed Neurological; Teratogen; Wasting Alkaloids; Swainsonine Forb Early spring emergence; addictive; equines susceptible
Atriplex spp Saltbush See List For Selenium Toxicosis Selenium Forb  
Avena fatua Wild oat grass See List For Nitrate Toxicosis Nitrates Grass Wild oats
Berteroa incana Hoary alyssum GI; Founder; Laminitis; Edema Unknown Forb  
Blighia sapida Akee Teratogenic; Fetal Teratogens Tree  
Brassica rapa Field mustard Gastric/Diarrhea; Anorexia Glucosinolates Forb  
Bromus tectorum Cheatgrass Mouth/Digestive Tract Physical Grass Downy brome
Bromus tectorum Downy brome Mouth/Digestive Tract Physical Grass Cheatgrass
Bryonia cretica White bryony Sweating; Diuresis; Convulsions Lectine; Polyhydroxic Acids Browse Berries; sap; roots; worse when dried
Buxus spp. Boxwood Neurologic; Colic; Respiratory Cyclobuxin (Alkaloid) Shrub All plant parts toxic
Caltha palustris Marsh marigold GI Irritant; Colic/Diarrhea Protoanemonin Forb  
Calycanthus floridus Sweet bubby Tetany; Convulsions; Neurological Calycanthin; Alkaloids Shrub Sweet shrub
Calycanthus floridus Sweetshrub Tetany; Convulsions; Neurological Calycanthin; Alkaloids Shrub Sweet bubby
Cannabis sativa Hemp Neurotoxin 60 Compounds Forb Marijuana
Cannabis sativa Marijuana Neurotoxin 60 Compounds; THC Forb Hemp  
Capsella bursa-pastoris Shepherd's purse Teratogenic Teratogens Forb Deformed foals
Cassia occidentalis Coffee weed Lameness; Muscle Weakness Anthraquinone Forb Sienna weed
Cassia occidentalis Sienna weed Colic/Diarrhea; Ataxia; Weakness Anthraquinone Forb Coffee weed
Castilleja linariaefolia Indian paintbrush See List For Selenium Toxicosis Se Accumulator Forb  
Celastrus scandens Climbing bittersweet Neurological; Gastric Solanine Browse Nightshades
Cenchrus longispinus Longspine sandbur Mouth/GI Physical Forb Sandbur
Cenchrus longispinus Sandbur Mouth/GI Physical Forb Longspine sandbur
Centaurea solstitialis Yellow starthistle Chewing Disease Alkaloids; Sesquiterpenes Forb Russian knapweed; no recovery; addictive
Cephalanthus occidentalis Button bush Gastrointestinal Glycosides Shrub  
Cercocarpus spp. Mountain mahogany Cardiac Cyanide Tree  
Cestrum diurnum Jessamine, day blooming Calcinosis; Lameness/Weakness Hyoscine Tree Wild jasmine
Cestrum diurnum Wild jasmine Calcinosis; Lameness/Weakness Hyoscine Tree Jessamines
Cestrum nocturnum Jessamine, night blooming Lameness/Muscle Weakness Atropine-like Alkaloids Tree  
Chenopodium album Lambsquarters See List For Nitrate Toxicosis Nitrates Forb  
Chorispora tenella Blue mustard Deformed Foals Glucosinolates Forb  
Cicuta douglasii Water hemlock Tremors; Convulsions; Death Cicutoxin Forb Western water hemlock; single mouthful; death in minutes
Cicuta douglasii Western water hemlock Tremors; Convulsions/ Death Cicutoxin Forb Water hemlock; single mouthful; death in minutes
Cirsium arvense Canada thistle See List For Nitrate Toxicosis Nitrates Forb  
Cirsium vulgare Bull thistle See List For Nitrate Toxicosis Nitrates Forb  
Clematis spp. Clematis Colic/Diarrhea; Neurotoxic Protoanemonin (Alkaloid) Browse All plant parts
Colchicum autumnale Autumn crocus Teratogenic; Fetal; Neurologic Teratogens Browse Meadow saffron
Colchicum autumnale Meadow saffron Teratogenic; Fetal Teratogens