Deadly Nightshade (Atropa Belladonna)
Belladonna is one of the most toxic plants found in the Eastern Hemisphere. All parts of the plant contain tropane alkaloids. 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 a human adult is probably lethal.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.
Water Hemlock (Cicuta Maculata)
The plant is occasionally mistaken for parsnips, due to its clusters of white tuberous roots; this is an often fatal error, as the Cicuta is extremely poisonous. Indeed, spotted water hemlock is considered to be North America’s most toxic plant. Cicuta is fatal when swallowed, causing violent and painful convulsions. Though a number of people have died from water hemlock poisoning over the centuries, livestock have long been the worst affected (hence the name “cowbane”), causing death in as little as 15 minutes
Castor Bean (Ricinus Communis)
The toxicity of raw castor beans is due to the presence of ricin. Although the lethal dose in adults is considered to be four to eight seeds, reports of actual poisoning are relatively rare. According to the 2007 edition of Guinness World Records, this plant is the most poisonous in the world. Symptoms of overdosing on ricin, which can include nausea, diarrhea, tachycardia, hypotension and seizures persisting for up to a week. However, the poison can be extracted from castor by concentrating it with a fairly complicated process similar to that used for extracting cyanide from almonds.
If ricin is ingested, symptoms may be delayed by up to 36 hours but commonly begin within 2–4 hours. These include a burning sensation in mouth and throat, abdominal pain, purging and bloody diarrhea. Within several days there is severe dehydration, a drop in bloodpressure and a decrease in urine. Unless treated, death can be expected to occur within 3–5 days, however in most cases a full recovery can be made.
White Snakeroot (Ageratina Altissima)
White snakeroot contains the toxin tremetol; when the plants are consumed by cattle, the meat and milk become contaminated with the toxin. When milk or meat containing the toxin is consumed, the poison is passed on to humans. If consumed in large enough quantities, it can cause tremetol poisoning in humans. The poisoning is also called milk sickness, as humans often ingested the toxin by drinking the milk of cows that had eaten snakeroot.
Tobacco (Nicotiana Tabacum)
Tobacco – most grown commercial plant in the world and all the parts of it, especially the leaves, contain nicotine and anabasine. These are toxic alkaloids-fatal if they are eaten. Despite of being labeled as a cardiac poison, nicotine is consumed around the world. It is perhaps most deadly plant – it causes 5 million deaths every year all around the world.
Rosary Pea (Abrus Precatorius)
The toxin abrin is a dimer consisting of two protein subunits, termed A and B. The B chain facilitates abrin’s entry into a cell by bonding to certain transport proteins on cell membranes, which then transport the toxin into the cell. Once inside the cell, the A chain prevents protein synthesis by inactivating the 26S subunit of the ribosome. One molecule of abrin will inactivate up to 1,500 ribosomes per second.
In the Oak woodlands of Western North America live edible bulbs known as Camas. But, toxicoscordion venenosum, is the most toxic plant that looks similar to edible Camas. Death Camas has different coloration. Now, consuming smallest amount can result with organ failure, blood disturbance and unfortunately, death.
Spurge Laurel – related to Bay Leaf, found in public grounds and ornamental gardens. It contains powerful biocides that cause irritation and blistering, when plant is cutted. But if berries are consumed it cause major internal bleeding and organ failure and death after several hours.
Tribes used this plant as a drug for seriously ill patients.