This list is compiled from a variety of poison plant lists and reports that have been received from many sources. A large portion of this list was compiled by Jayne Cuny and originally published in Practical Koi Keeping, Volume II. The authenticity and source of many entries cannot be traced which makes it easier for a plant to get on this list than to get off of it. Note that there is no scale of relative toxicity included so a plant that might produce minor problems to a few is listed alongside those that could be lethal to all. Please send any comments, or candidates for addition or removal with rationale, to normeck@pacbell.net.
| ACOKANTHERA | fruit & flowers |
| ACONITUM | (Aconite, Monkshood) roots, flowers, & leaves |
| ANENOME | (Wildflower) all parts |
| AMARYLLIS | (A. Belladonna) bulbs contain alkaloids |
| ANGEL TRUMPET TREE (Datura Arborea) | flowers & leaves |
| APPLE | (See Cherry Laurel) |
| APRICOT | (See Cherry Laurel) |
| ATROPA BELLADONNA | all parts, especially black berries |
| AUTUMN CROCUS (C. Sativus, Saffron Crocus) | bulbs |
| AZALEAS (Rhododendorn) | all parts can be fatal |
| BANEBERRY (Actaea, Doll's Eyes) | red or white berries, roots & foliage |
| BEACH PEA (Lathyrus Maritimus) | stems |
| BETEL NUT PALM | all parts |
| BIRD OF PARADISE BUSH (Caesalpinia) | seeds |
| BITTERSWEET (Celastrus) | berries |
| BLACK LOCUST (Robinia Pseudoacacia) | bark, sprouts, & foliage are poisonous |
| BLEEDING HEART (Dicentra, Dutchman's Breeches) | foliage & roots |
| BLUEBONNETS (Lupinus) | all parts |
| BOTTLEBRUSH (Callistemon, possibly Melaleuca) | flowers |
| BOXWOOD (Buxus Sempervirens) | all parts |
| BUCKEYE (Aesculus, Horse Chestnut) | sprouts and nuts |
| BUTTERCUP (Ranuculus, Crowfoot) | all parts |
| CALADIUM | all parts |
| CALLA LILY (Zantedeschia) | leaves |
| CAROLINA JESSAMINE (Gelsemium) | All parts |
| CASTOR BEAN (Ricinus Communis) | seeds can be fatal |
| CHERRY | see Cherry Laurel |
| CHERRY LAUREL (Prunus Varieties) | all parts, seeds contain hydrocyanic acid |
| CHINABERRY (Melia Azedarach) | berries are poisonous |
| CHRISTMAS BERRY (Heteromeles Arbutifolia, Toyon) | berries are poisonous |
| COLUMBINE (Aquilegia) | all parts |
| COMMON PRIVET (Ligustrum) | black or blue wax coated berries and leaves |
| CORAL BERRY (Symphoricarpos) | seeds |
| CROCUS | all bulbs |
| DAPHNE | berries can be fatal |
| DAFFODIL (Narcissus) | bulbs may be fatal |
| DATURA (Brugmansia) | flowers, berries, & seeds |
| DEATH-CAMAS (Sygadenus Venous) | all parts poisonous, roots are deadly |
| DEADLY NIGHTSHADE (Solanum Nigrum) | all parts, unripe fruit & foliage |
| DELPHINIUM (Larkspur annual) | all parts |
| DESTROYING ANGEL (Amanita Phalloides, Death Cup) | all parts |
| DIEFFENBACHIA (Dumb Cane) | all parts, especially the sap |
| DOGWOOD (Cornus) | fruit slightly poisonous |
| EGGPLANT | all but fruit |
| ELDERBERRY (Sambucus) | red fruit poisonous, black & blue fruit o.k. |
| ELEPHANT EAR (Colocasia, Taro, Caladium) | stem & leaves |
| ENGLISH IVY (Hedera Helix) | berries |
| EUPHORBIA (Splurge, Gopher Plant, Mole Plant) | roots, sap |
| FALSE HELLEBORE (Veratrun Viride & other species) | all parts poisonous, root deadly |
| FOXGLOVE (Digitalis Purpurea) | all parts can be fatal |
| FLY AGARIC (Fly Amanita Mushroom) | whole plant |
| FOUR O'CLOCK | whole plant |
| GELSEMIUM (Carolina Jessamine) | whole plant |
| GOLDEN CHAIN | seeds & pods may be fatal |
| HELLEBORE (Ranunculaccea) | all parts |
| HEMLOCK (Tsuga) | all parts, especially roots |
| HENBANE | all parts |
| HOLLY (Ilex Aquifolium, Opaca, Vomitoria) | leaves & berries |
| HORSE CHESTNUT (Aesculus, Buckeye) | all parts |
| HORSETAIL (Equisetum Hyemale) | all partt |
| HYACINTH | bulbs can be fatat |
| HYDRANGEA | whole plant |
| IMPATIENS (Balsam, Touch-Me-Not, Snapweed) | whole plant |
| IRIS | underground stemt |
| IVY (Hedera) | all parts |
| JACK-IN-THE-PULPIT (Arisaema Triphylla) | root is irritant & astringent |
| JASMINE, YELLOW | all parts |
| JERUSALEM CHERRY (Solanum Pseudocapsicum) | fruit & leaves |
| JESSAMINE (Gelsemium Sempervirens) | berries are fatal |
| JIMSON WEED (Datura Stramomium, Thorn Apple) | all part |
| LAMBKILL (Kalmia Angustifolia, Sheep Laurel) | leaves |
| LANTANA CAMARA (Red Sage) | green berries are fatal |
| LARKSPUR (Delphinium) | foliage & roots are dangerous, seeds may be fatal |
| LAUREL (Primus varieties) | all parts can be fatal |
| LILY (Lilium) | some varieties bulbs |
| LILY-OF-THE-VALLEY (Convallaria Majalis) | all parts |
| LOBELIA (Cardinal Flower) | all parts |
| LOCOWEED (Astragalus, Oxytropis) | all parts |
| LUPINE (Lupinus) | seeds |
| MACHINEEL | all parts |
| MARIJUANA | all parts |
| MAY APPLE (Podophullum) | all parts |
| MESCAL (Peyote) | all parts |
| MILKWEED (Asciepias) | all parts, especially sap |
| MISTLETOE | berries can be fatal |
| MOCCASIN FLOWER (Lady Slipper, Cypripedium Spectabiles) | all parts |
| MOCK ORANGE (Philadelphus) | all parts |
| MONKSHOOD (Aconitum) | foliage & fleshy roots |
| MORNING GLORIES (Ipomea) | all parts |
| MOUNTAIN LAUREL (Kalmia Latifolia) | young leaves & shoots, can be fatal |
| MUSHROOMS | wild types |
| NARCISSUS (Daffodil) | bulbs can be fatal |
| NATAL CHERRY (Solanum) | berries |
| NICOTIANA (Flowering Tobacco) | leaves |
| NIGHTSHADE (European Bittersweet, Horse Nettle) | all, especially unripe berries |
| OAK | foliage & acorns |
| OLEANDER (Nerium Oleander) | All parts poisonous including smoke if burned |
| PEACH see Cherry Laurel, | seeds |
| PEAR see Cherry Laurel, | seeds |
| PEONY (Paeonia) | all parts |
| PERIWINKLE (Vinca, Myrtle) | whole plant |
| PHILODENDREN | leaves & sap |
| PINE | sap |
| PINKS (Sweet William, Carnation, Dianthus) | all parts |
| PLUM see Cherry Laurel, | seeds |
| POKEWEED (Phytolacca, Pokeberry) | roots are dangerous |
| POINSETTIA (Euphorbia Pulcherrima) | leaves & sap can be fatal |
| POISON IVY (Rhus Radicans) | all parts |
| POISON OAK (Rhus Diversioba, Rhus Toxicondendron) | all parts |
| SUMAC (Rhus) | all parts |
| POPPY (Papaver) | all except California Poppy can be dangerous |
| POTATO | sprouts and foliage can be fatal particularly ornamental varieties |
| PRIVET (Ligustrum) | leaves & fruit |
| PRUNUS (many varieties) | seeds, some parts |
| RANUNCULUS | all parts |
| REDWOOD | sap |
| RHODODENDRON (Azalea) | all parts can be fatal |
| RHUBARB (Rhenum Rhaponticum) | leaves, stems OK for human consumption |
| ROSEMARY (Rosemarius Officinalis) | leaves of certain varieties are poisonous |
| SAGE (Salvia) | leaves of certain varieties are poisonous |
| SCOTCHBROOM (Cytinsus Scoparious) | seeds, invasive |
| SENECIO | whole plant of some species |
| SOLANUM (Nightshade) | all, especially some berries |
| SNAPDRAGON (Antirrhinum) | all parts |
| SNOWDROP (Galanthus) | all parts |
| SQUIRREL CORN (Dicentra Canadensis, Bleeding Heart) | all parts |
| STRAMONIUM (Jimson Weed, Datura) | all parts |
| SWEET PEA (Lathyrus) | stems |
| TANSY (Tanacetum) | all parts |
| TARO (Colocasia, Elephant's Ear) | stem & leaves |
| TIGER LILY (Lilium Tigrinum) | all parts |
| TOADSTOOLS | can be fatal |
| TOBACCO | all parts |
| TOMATO | foliage & vines |
| TULIP (Tulipa) | bulbs of some varieties |