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10 Plants That Want to Straight Up Kill You (And Can)
By Adrian Chirila,
Toptenz, 15 November 2016.

On one of her visits to Italy, the Duchess of Northumberland was inspired by the Medici family, and with one of their botanical gardens in particular. Like the Italian family of old, the Duchess decided to design a garden at her castle in Alnwick, filled with over 100 of the most poisonous plants around the world. Some plants there are so dangerous they’re caged, while others even require government approval to be grown. For some, this garden might even look somewhat familiar since the first two Harry Potter movies were partially filmed there.

You’d be surprised at just how many poisonous plants are out there. Unlike people, or the animal kingdom for that matter, plants don’t have the ability to move around and run from danger. That’s why some have developed thorns, others became spicy, and others downright deadly. Below we’ll be discussing 10 of the most deadly poisonous plants in the world.

10. Tobacco


Please don’t get us wrong, we’re not trying to make any anti-smoking campaigns here, but we do have to take a look at some facts about tobacco here. Firstly, all of the plant’s parts, especially its leaves, contain anabasine and nicotine alkaloids. And both of these compounds are toxic by the way. Mimicking the effects of acetylcholine, a naturally-occurring molecule in charge of stimulating muscle tissue, nicotine acts primarily on the autonomic nervous system. If eaten, the tobacco plant can be fatal. A dose of 50 mg can cause respiratory failure and general paralysis. Smaller doses of nicotine can cause heart palpitations, high blood pressure, nausea, and dizziness. One cigarette contains about 3 mg of nicotine, making up between 0.6 and 3% of dry weight of tobacco, and gives a sense of alertness and well-being. By “tickling” the pleasure receptors, nicotine is also highly addictive and causes withdrawal symptoms in smokers if they try to quit, or have run out.

Nicotine in liquid form has an oily texture, a yellowish color and turns brown on exposure with air. A tablespoon full can kill a full-grown man and even skin-contact is enough to cause symptoms of poisoning, such as dizziness, elevated blood pressure and seizures. This liquid nicotine is used in the controversial e-cigs and as insecticide. An estimated 5 to 6 million people die annually from tobacco related causes. Even so, tobacco is the most widely grown commercial non-food plant in the world.

9. Deadly Nightshade


With a name like that, it’s no wonder this plant made it on this list. More commonly known as Belladonna, or even Devil’s berries, the Atropa belladonna is common throughout Southern and Central Europe, Northern Africa, Western Asia, and with the arrival of Europeans to the New World, in some parts of Canada and the US. The Deadly Nightshade is also related to the tomato, potato, the eggplant, some peppers, and the above mentioned tobacco; all being part of the Solanaceae family. Among the most poisonous plants in the Eastern Hemisphere, Nightshade contains large amounts of Tropane alkaloid, alongside some other toxins.

Under strict medical supervision, tropane extract has some pharmacological properties and is used in various therapeutic procedures, and has been used as an anesthetic for surgery in ancient times.   Depending on the season, and the plant’s vegetation period, the level of toxicity varies between the various parts of the Belladonna. In theory three to four fresh berries act as a psychoactive aphrodisiac. But based on each individual person’s health and physique, the stage of vegetation the plant is in - which varies from plant to plant- the risk of an accidental lethal dose is extremely high. Children are the most in danger from the Nightshade, because of its big and slightly sweet berries, which really look appealing.

The word Belladonna means “pretty woman” in Italian, and most likely refers to the plant being used either as a cosmetic during medieval times, or for dilating the eye pupils, in order to make girls look more attractive. Atropa refers to the Ancient Greek, Atropos, one of the three Fates, who held the shears which could cut the thread of life. It was also used as a poison by the Ancient Romans, and to make poison-tipped arrows. The story goes that before becoming king in 1040, Macbeth (the actual king, not the Shakespeare character) used Nightshade to poison an entire Danish army who invaded Scotland.

8. Water Hemlock


Another seemingly inconspicuous plant, found in abundance all throughout the northern temperate regions of the world, is the Water Hemlock or Cicuta. While Socrates is said to have been forced to drink poison hemlock when he was believed to have conspired with the short-lived Spartan reign over Athens, water hemlock is considered the most violently toxic plant in North America. Part of the parsley family like carrots, parsnips, celery, and coriander, among others, water hemlock is typically found growing in moist habitats, such as drainage ditches, marshes, and near various bodies of fresh water. And only a small amount of its toxic, cicutoxin, is enough to poison humans and cattle alike. Cicutoxin acts directly on the central nervous system, resulting in violent convulsions.

Water hemlock is quite identifiable, especially in June and July, when its flowers are in bloom. They are small, white, and grow in umbrella-shaped clusters known as umbels. The most poisonous part of the hemlock is its roots. Cattle have been known to eat them, or the plant’s green seed heads, which often times resulted in the animal’s death. Ranging from 6 hours to a mere 15 minutes after eating the hemlock, both animals and humans begin to show symptoms of poisoning. These include: nervousness, excessive salivation and frothing, muscle twitching, dilation of the pupils, rapid pulse, rapid breathing, tremors, violent convulsions, grand mal seizures, coma and almost certain death.

7. The Rosary Pea


Native to Indonesia but found in other places around the world, Abrus precatorius goes by many names: rosary pea, jequirity, paternoster pea, crab’s eye, precatory bean, Indian licorice, love pea or Jumbie bread. This plant is known for its brightly red and black seeds, which are often times used in percussion instruments such as maracas, or as jewelry. In fact, their name “rosary pea” stems from when people used to string them together to form rosary beads. Because of their religious purpose among others, its seeds have been carried far and wide, and the plant has since become an invasive species throughout most of the warm temperate to tropical regions of the world, from Belize to Hawaii, Polynesia and especially Florida.

The scary part about these seeds, however, is that they’re extremely poisonous. Abrin, the active toxin inside, is between 75 and 100 times more deadly than ricin, a poison found in other dangerous plants, including castor seeds. Just 3 mg of the stuff are enough to kill a man. Fortunately, however, the seeds have a tough outer shell which holds the deadly poison inside. Even if ingested, the seeds won’t necessarily have any effect and will pass safely through the digestive system. But if the shell if cut or broken, things can turn nasty. There have even been cases of jewelry makers pricking a finger while working with the rosary peas, and dying soon after.

6. Oleander


Believe it or not, this beautiful-looking evergreen shrub, especially praised for its striking flowers since the time of the Ancient Romans, is the most poisonous commonly grown garden plant. Originally from Asia, but not known for sure due to its wide distribution, oleander can be found from Portugal all the way to southern China, the Arabian Peninsula and the Sahara. Typically occurring around dry stream beds, the tree is planted throughout much of the subtropical and tropical areas of the world. However, oleander is a popular decorative plant in North America.

Oleander grows between 6 and 20 feet tall, and its flowers grow in clusters at the end of each branch. If by any chance someone or something eats from it, they almost immediately begin to feel the effects of cardiac and gastrointestinal symptoms. Among the many nasty effects of oleander are: bloody diarrhea, vomiting, drooling, blurred vision, nausea, fainting, irregular heartbeat and death. Toxins such as cardiac glycosides, neriin and oldendrin all contribute to oleander’s lethal mix, and swift medical treatment is essential for survival. Every part of the plant is toxic, including its nectar, and there have even been reports of people suffering from serious poisoning after inhaling the smoke resulting from using the twigs as cooking skewers.

5. Angel’s Trumpet


Brugmansia, as it is officially called, is a genus of seven species of flowering plants - all poisonous. Reaching as high up as 36 feet in some cases, its most notable feature and the main reason for why it’s such a popular decorative tree, is its pendulous flowers, which resemble trumpets. These flowers come in a variety of sizes and colors, ranging from 6 to 20 inches and being either white, yellow, orange, or pink. Native to the tropical regions of South America from the Andes to Venezuela, as well as southeast Brazil, all seven of these plants have been classified as extinct in the wild. However, they are still found in the wild, in various places where the species are classified as invasive.

All parts of this plant are poisonous, especially its seeds and leaves, and may be fatal if ingested by humans or animals. Brugmansia are rich in scopolamine, hyoscyamine, and several other tropane alkaloids. If ingested, the effects can include paralysis of smooth muscles, confusion, tachycardia, dry mouth, diarrhea, migraines, visual and auditory hallucinations, a rapid onset cycloplegia, and death. These alkaloids mentioned above have proven some medicinal values. The plant was also traditionally used by local tribes in various ceremonies. Mixed with corn beer and tobacco leaves, it has been used to drug wives and slaves before being buried alive with their dead lord. From the Angel’s Trumpet also comes the “Devil’s Breath”.

This is, according to some, the “world’s scariest drug” and with a justified reason. Made into powder form, scopolamine inhibits the formation of new memories, and blocks free will, thus leaving people extremely vulnerable to their surroundings. In short, by blowing the powder in someone’s face, you can turn them into “zombies.

4. Queen of all Poisons


A name like that isn’t just given away willy-nilly, it has to be earned. The plant in question also goes by a series of other different names, like monkshood, wolf’s bane, leopard’s bane, mouse bane, women’s bane, devil’s helmet, or even blue rocket. Part of the Aconitum genus alongside some 200 other flowering plants, the Queen grows in damp, mountainous conditions throughout North America, Europe and parts of Asia. Its various other names come from the many uses this plant, and especially its poison, had throughout the centuries. It also has somewhat of a resemblance to the hoods monks used to wear.

Growing to about 6 feet tall, the entire plant is poisonous, even the nectar it produces. The toxin inside is called Aconitine and 20 to 40 ml of it can prove fatal to an average adult 2 to 6 hours after ingestion. The first signs of poisoning include nausea, vomiting, and diarrhea. Then the sensations of numbness, burning and tingling set in, quickly followed by a pronounced motor weakness and ventricular arrhythmias. These in turn will lead to paralysis of the heart and respiratory system which we all know what they cause. Poisoning can also occur by simply touching or picking the leaves since aconitine is easily absorbed through the skin.

In older times, different peoples and tribes throughout the world used to hunt or wage war by dipping their spears or arrows in this toxin. From Alaska, Greece, Nepal, China, to Japan, people used it to deadly effect. In Alaska for example, the Aleut people would go on a kayak and with a poison tipped spear would hunt whales or seals, paralyzing them with the poison and causing them to drown. Monkshood is considered to be the deadliest plant in Europe.

3. White Snakeroot


Native to eastern and central North America, White Snakeroot grows to about 5 feet tall and is usually fond of wooded areas. This is not always the case, since Snakeroot is easily adaptable and can also be found in open shady areas. The plant is easily recognizable, especially in mid to late summer or fall, due to its small, clear-white flowers, which grow in clumps. Its seeds are small, fluffy and with a white tail, perfect for being blown by the wind.

Its active poison is called tremetol and when it’s eaten by cattle or other animals, the toxin contaminates their meat and milk. If humans consume these products of an infected animal, they too become poisoned. When large numbers of Europeans began settling the midwest and upper south United States during the 19th century, they were unaware of Snakeroot, and many thousands died because of it. Not knowing what was happening; people began calling the phenomenon “milk sickness.” Abraham Lincoln’s mother is said to have died of it back in 1818. Decades passed before people realized who the real culprit was. Dr. Anna Pierce Hobbs Bixby is credited with identifying the plant during the 1830s when she learned about its deadly effects from a Shawnee woman.

2. The Manchineel Tree


Growing in South and Central America, through the Caribbean and all the way north to the Floridian Everglades, the Manchineel is considered by many to be the most dangerous tree in the world. In some places the tree even has a red cross painted on it, in order to warn any passersby of the danger they’re in. Simply brushing past it can leave the skin severely scalded. Someone standing beneath it while it’s raining isn’t safe, either. As rainwater pours through the leaves, it comes in contact with the sap, and when the solution touches the skin, it forms blisters. Burning the wood is equally as bad as the smoke can cause blindness and severe respiratory problems.

The most poisonous parts of the tree are its fruits. Known in Spanish as “the little apples of death,” eating one will most certainly cause death. Because of its pain-inflicting capabilities, the native people from the Caribbean used to poison wells with the sap, or dip their arrows in it, as well as to occasionally tie someone to the tree so he could die in agony. Juan Ponce de León may have been killed by the Calusa warriors in this manner in 1521.

1. The Suicide Tree


Another dangerous tree, and the last entry in this list, comes this time from India, Madagascar and Southeast Asia. Though seemingly inconspicuous, Cerbera odollam hides a deadly secret within its seeds. Being a relative of the above mentioned Oleander, its toxins act in a somewhat similar way. The Suicide Tree draws its name from the fact that people use it to poison themselves. It is estimated that around 50 people meet this self-inflicted end each year in the state of Kerala, India, alone. But if something’s good for suicide, it’s also good for murder. The seed’s what contains all the poison, and if someone was to crush it into a fine powder and mix it in with all the spicy Indian food and give it to someone else, who’s to know, right?

In fact cerberin, the toxin found in these seeds, is undetectable by most toxicology reports, and someone has to specifically look for cerberin to actually find it. Looking for the toxin requires the use of high-performance liquid chromatography coupled with mass spectrometry in order to be detected, a process which is quite costly, especially in India. Because of this, most cases of cerberin poisoning go unnoticed, but even so, at least one person dies of it per week in Kerala. In Madagascar up until the mid-19th century people suspected of witchcraft were subject to the “trial by Tagena” where they were forced to eat one such seed. Those few who survived were considered innocent; the others, well…died.

Things gotten so out of hand that by the time King Radama II banned the practice in 1861, it was estimated to have killed around 2 percent of the island’s entire population per year; roughly 3,000 people. This trial is still believed to take place even to this day in some remote parts of Madagascar.

Top image: Manchineel tree warning sign. Credit: ellentk/Flickr, CC BY-NC-ND 2.0.

[Source: Toptenz. Edited. Top image added.]