rarely, however, as toxic compounds in the potato plant are generally concentrated in the green portions of the plant and in the fruits, and cultivated varieties contain smaller concentrations than wild plants. cooking at high temperatures (over 170 °c or 340 °f) also partly destroys the toxin. however, exposure to light, physical damage, and age can increase glycoalkaloid content within the tuber, the highest concentrations occurring just underneath the skin. tubers that are exposed to light turn green from chlorophyll synthesis, thus giving a visual clue as to areas of the tuber that may have become more toxic; however, this does not provide a definitive guide, as greening and glycoalkaloid accumulation can occur independently of each other. some varieties of potato contain greater glycoalkaloid concentrations than others; breeders developing new cultivars try to keep solanine levels below 200 mg/kg (200 ppmw). however, when these commercial varieties turn green, even they can approach solanine concentrations of 1000 mg/kg (1000 ppmw). the u.s. national toxicology program suggests that the average american consume no more than 12.5 mg/day of solanine from potatoes (the toxic dose is several times this, depending on body weight). vitis spp. grape potentially toxic to dogs, although the precise mechanism is not fully understood. see grape and raisin toxicity in dogs. other poisonous plants countless other plants not commonly used in food or drink are also poisonous, and care should be taken to avoid accidentally contacting or ingesting them. some of these are popular ornamental plants or are cultivated for purposes other than consumption. scientific name common name(s) description picture abrus precatorius known commonly as jequirity, crab's eye, rosary pea, 'john crow' bead, precatory bean, indian licorice, akar saga, giddee giddee, jumbie bead, ruti, and weather plant. the attractive seeds (usually about the size of a ladybug, glossy red with one black dot) contain abrin, an extremely toxic ribosome-inactivating protein related to ricin. symptoms of poisoning include nausea, vomiting, convulsions, liver failure, and death, usually after several days. ingesting a single seed can kill an adult human. the seeds have been used as beads in jewelry, which is dangerous; inhaled dust is toxic and pinpricks can be fatal. the seeds are unfortunately attractive to children. aconitum spp. several species commonly called aconite, wolfsbane, and monkshood. all parts are poisonous, containing an alkaloid called aconitine, which disables nerves, lowers blood pressure, and can stop the heart. even casual skin contact should be avoided. symptoms include numbness, tingling, and cardiac irregularity. it has been used as a poison for bullets (by german forces during world war ii), as a bait and arrow poison (ancient greece), and to poison water supplies (reports from ancient asia). if ingested, it usually causes burning, tingling, and numbness in the mouth, followed by vomiting and nervous excitement. it is usually a quick-acting poison and has been used in the past for killing wolves (hence one of the common names). actaea pachypoda also known as doll's eyes or white baneberry. all parts are poisonous, especially the berries, the consumption of which has a sedative effect on cardiac muscle tissue and can cause cardiac arrest. adenium obesum also known as sabi star, kudu, or desert-rose. the plant exudes a highly toxic sap which is used by the meridian high and hadza in tanzania to coat arrow-tips for hunting. adonis vernalis known variously as pheasant's eye and false hellebore. the plant is poisonous, containing cardiostimulant compounds such as adonidin and aconitic acid. aesculus hippocastanum commonly known as horse-chestnut. all parts of the plant are poisonous, causing nausea, muscle twitches, and sometimes paralysis. agave spp. also known as century plant and maguey the juice of several species causes acute contact dermatitis, with blistering lasting several weeks and recurring itching for several years thereafter. ageratina altissima commonly known as white snakeroot. all parts contain a toxic oil known as tremetol, which causes nausea and vomiting and is often fatal. milk sickness is caused by drinking milk from cattle that have eaten white snakeroot, which can sicken or kill humans. agrostemma githago commonly known as corn cockle. contains the saponins githagin and agrostemmic acid. all parts of the plant are reported to be poisonous and may produce chronic or acute, potentially fatal poisoning, although it has been used in folk medicine to treat a range of ills, from parasites to cancer. there are no known recent clinical studies of corn cockle which provide a basis for dosage recommendations; however, doses higher than 3 g (of seeds) are considered toxic. anemone nemorosa common names include wood anemone, windflower, and thimbleweed. the plant contains chemicals that are toxic to animals including humans, but it has also been used as a medicine. all parts of the plant contain protoanemonin, which can cause severe skin and gastrointestinal irritation, bitter taste and burning in the mouth and throat, mouth ulcers, nausea, vomiting, diarrhea, and hematemesis. anthurium spp. common names include anthurium, tailflower, and flamingo flower. anthurium plants are poisonous due to calcium oxalate crystals. the sap is irritating to the skin and eyes. aquilegia spp. many species commonly known as columbine. seeds and roots contain cardiogenic toxins which cause both severe gastroenteritis and heart palpitations if consumed. the flowers of various species were consumed in moderation by native americans as a condiment with other fresh greens, and are reported to be very sweet and safe if consumed in small quantities. native americans also used very small amounts of the root as an effective treatment for peptic ulcers. however, medical use of this plant is difficult due to its high toxicity; columbine poisonings are easily fatal. areca catechu commonly known as betel nut palm and pinyang. the nut contains arecoline, an alkaloid related to nicotine which is addictive. it produces a mild high, some stimulation, and much red saliva, which cannot be swallowed as it causes nausea. withdrawal causes headache and sweats. use is correlated with mouth cancer, and to a lesser extent asthma and heart disease. argemone mexicana common names include mexican poppy, flowering thistle, cardo, and cardosanto. a. mexicana seeds contain 22–36% of a pale yellow non-edible oil called argemone oil or katkar oil, which contains the toxic alkaloids sanguinarine and dihydrosanguinarine. katkar oil poisoning causes epidemic dropsy, with symptoms including extreme swelling, particularly of the legs. arnica montana also known as mountain arnica. it contains the toxin helenalin, which can be poisonous if large amounts of the plant are eaten or small amounts of concentrated arnica are used. consumption of a. montana can produce severe gastroenteritis, internal bleeding of the digestive tract, raised liver enzymes (which can indicate inflammation of the liver), nervousness, accelerated heart rate, muscular weakness, and death if enough is ingested. contact with the plant can also cause skin irritation. in the ames test, an extract of a. montana was found to be mutagenic. the plant's toxicity has led to the usfda officially declaring it to be unsafe. arum maculatum commonly known as cuckoo-pint, lords and ladies, jack-in-the-pulpit, wake robin, wild arum, devils and angels, cows and bulls, adam and eve, bobbins, and starch-root. all parts of the plant can produce allergic reactions. the bright red berries contain oxalates of saponins and can cause skin, mouth, and throat irritation, resulting in swelling, burning pain, breathing difficulties, and stomach upset. one of the most common causes of plant poisoning. atropa belladonna commonly known as deadly nightshade, belladonna, devil's cherry, and dwale. one of the most toxic plants found in the western hemisphere, all parts of the plant contain tropane alkaloids – as do those of its equally deadly sister species a. baetica, a. pallidiflora and a. acuminata. the active agents are atropine, hyoscine (scopolamine), and hyoscyamine, which have anticholinergic properties. the symptoms of poisoning include dilated pupils, sensitivity to light, blurred vision, tachycardia, loss of balance, staggering, headache, rash, flushing, dry mouth and throat, slurred speech, urinary retention, constipation, confusion, hallucinations, delirium, and convulsions. the root of the plant is generally the most toxic part, though this can vary from one specimen to another. ingestion of a single leaf of the plant can be fatal to an adult. casual contact with the leaves can cause skin pustules. the berries pose the greatest danger to children because they look attractive and have a somewhat sweet taste. the consumption of two to five berries by children and ten to twenty berries by adults can be lethal. in 2009, a case of a. belladonna being mistaken for blueberries, with six berries ingested by an adult woman, was documented to result in severe anticholinergic syndrome. the plant's deadly symptoms are caused by atropine's disruption of the parasympathetic nervous system's ability to regulate involuntary activities such as sweating, breathing, and heart rate. the antidote for atropine poisoning is physostigmine or pilocarpine. a. belladonna is also toxic to many domestic animals, causing narcosis and paralysis. however, cattle and rabbits eat the plant seemingly without any harmful effects. in humans, its anticholinergic properties will cause the disruption of cognitive capacities like memory and learning. brugmansia spp. commonly known as angel's trumpet. all parts of all plants in this genus contain the tropane alkaloids scopolamine and atropine; often fatal. these plants are closely related to and were once grouped with members of the genus datura, which contain the same deadly alkaloids. effects of ingestion may include losing connection with reality and hallucinations. an unfortunate case has been reported in the neuroscience literature about a young man performing self-amputation with pruning shears after intentionally ingesting brugmansia tea, boiled from just two flowers. caladium spp. commonly known as angel wings, elephant ear, and heart of jesus. all parts of all plants in this genus are poisonous. symptoms are generally irritation, pain, and swelling of tissues. if the mouth or tongue swell, breathing may be fatally blocked. calla palustris also known as marsh calla, wild calla, and water-arum. the plant is very poisonous when fresh due to its high oxalic acid content, but the rhizome (like that of caladium, colocasia, and arum) is edible after drying, grinding, leaching, and boiling. caltha palustris commonly known as marsh-marigold and kingcup. it contains several active substances of which the most important from a toxicological point of view is protoanemonin. ingesting large quantities of the plant may cause convulsions, burning of the throat, vomiting, bloody diarrhea, dizziness, and fainting. contact of the skin or mucous membranes with the juices can cause blistering or inflammation, and gastric illness if ingested. younger parts seem to contain lower toxin concentrations and heating breaks these substances down. small amounts of caltha in hay do not cause problems when fed to livestock, but larger quantities can lead to gastric illness. cascabela thevetia also known as yellow oleander. all parts of the plant are toxic to most vertebrates as they contain cardiac glycosides. many cases of intentional and accidental poisoning of humans are known. cephalanthus occidentalis commonly called buttonbush. it has several historical medicinal uses, but it is also toxic due to the presence of cephalathin. cerbera odollam commonly known as the suicide tree. the seeds contain cerberin, a potent toxin related to digoxin. the poison blocks the calcium ion channels in heart muscle, causing disruption of the heartbeat. this is typically fatal and can result from ingesting a single seed. cerberin is difficult to detect in autopsies and its taste can be masked with strong spices, such as a curry. it is often used in homicide and suicide in india; kerala's suicide rate is about three times the indian average. in 2004, a team led by yvan gaillard of the laboratory of analytical toxicology in la voulte-sur-rhône, france, documented more than 500 cases of fatal cerbera poisoning between 1989 and 1999 in kerala. they said "to the best of our knowledge, no plant in the world is responsible for as many deaths by suicide as the odollam tree." a related species is cerbera tanghin, the seeds of which are known as tanghin poison nut and have been used as an 'ordeal poison'. chelidonium majus also known as greater celandine. the whole plant is toxic in moderate doses as it contains a range of isoquinoline alkaloids, but there are claimed to be therapeutic uses when used at the correct dosage. the main alkaloid present in the herb and root is coptisine, with berberine, chelidonine, sanguinarine, and chelerythrine also present. sanguinarine is particularly