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The Top 10 Deadliest Plants in the World

Larry Slawson received his Master's Degree at UNC Charlotte. He has 15+ years of gardening experience, working with a variety of plants.

The Top 10 Deadliest Plants in the World.

The Top 10 Deadliest Plants in the World.

The World's Most Poisonous Plants

Throughout the world, there exists a number of plants capable of inflicting serious harm to humans (when ingested, inhaled, or injected). From Jimson Weed to the deadly Rosary Pea, this article examines the 10 deadliest and most dangerous plants in the world, ranking each of the species according to their potential for causing human fatalities.

Selection Criteria

In order to rank the world’s deadliest plants, a number of basic criteria were necessary for the extents and purposes of this work. First and foremost, each of the plants discussed below are ranked according to the overall potency of their toxins in relation to humans. Second, fatality rates based on consumption (ingestion), inhalation, or injection of these specimens is also considered. Finally, and perhaps most importantly, the average amount of time between exposure and death is considered with the assumption that no medical treatment (or care) was taken by an individual following contact with each plant. This final criterion is vital for this work, as a variety of antidotes (and treatment options) are available to counteract the toxic effects delivered by most plants.

While this selection process leaves room for potential flaws, the author believes that these criteria offer the best means for ranking the world’s deadliest plants.

The 10 Deadliest Plants Ranked

  • Jimson Weed
  • Hemlock
  • Devil’s Helmet
  • Water Hemlock
  • Oleander
  • White Snakeroot
  • Suicide Tree
  • Rosary Pea
  • Deadly Nightshade
  • Castor Bean Plant
Jimson Weed.

Jimson Weed.

10. Jimson Weed

  • Common Name: Jimson Weed
  • Binomial Name: Datura stramonium
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Solanales
  • Family: Solanaceae
  • Genus: Datura
  • Species: D. stramonium

Jimson Weed (also known as “Thorn Apple” or “Devil’s Snare”) is a highly toxic plant from the nightshade family. Although originally found throughout Central America, Jimson Weed is now found throughout all of the world’s warm and temperate regions. Today the plant is considered an invasive species for many parts of the globe as the weed is known to destroy local plant life.

In regard to its characteristics, Jimson Weed is an annual plant that grows upwards of 5 feet tall. Roots on the plant are long, white, and fibrous, whereas the stem of Jimson Weed is leafy, smooth, and thick. Generally speaking, the Jimson Weed’s stem displays a vibrant yellowish-green or reddish-purple coloration. Leaves are dark green and provide protection against the plant’s cream and violet colored flowers (which reach 2.5 to 3.5 inches in length). Jimson Weed is also quite fragrant, though many describe its overall scent as “foul.”

Signs and Symptoms of Jimson Weed Poisoning

Contrary to popular belief, all parts of the Jimson Weed plant are extremely toxic to animals and humans, alike. This is due to the abundance of atropine, scopolamine, and hyoscyamine that are present within the plant’s general structure. These substances, which are known as anticholinergics or deliriants, are extremely dangerous in higher doses and can result in death. Overall toxicity from the plant varies depending on its age, local weather, and region where it is growing. Younger plants, for example, tend to be less toxic than mature specimens.

Upon ingestion of the plant, symptoms of Jimson Weed poisoning usually begin within 30 minutes. This includes delirium, hallucinations, elevated heart rate (tachycardia), as well as hyperthermia (over-heating). Depending on the severity of the poison, individuals may also experience urinary retention, dilation of the eyes, photophobia, as well as the onset of bizarre behaviors.

Treatment

Jimson Weed poisoning is considered a medical emergency, and requires rapid treatment to mitigate the poison’s effects on the body. Treatment for Jimson Weed poisoning involves an intravenous dose of physostigmine, which acts as an inhibitor to the poison’s overall effects. This is generally followed by treatment of the individual’s specific symptoms, as well the administration of intravenous fluids to maintain hydration and electrolyte balance. Gastric suction (stomach pumping) may also be employed by doctors to remove Jimson Weed particles from the gastrointestinal tract.

Fortunately, these treatment options are known to have a 90-percent success rate, making deaths related to Jimson Weed poisoning rare in the Western Hemisphere (nih.gov). Nevertheless, rapid medical treatment should always be sought to prevent long-term injury or death.

Deadly Hemlock.

Deadly Hemlock.

9. Hemlock

  • Common Name: Hemlock or “Poison Hemlock”
  • Binomial Name: Conium maculatum
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Apiales
  • Family: Apiaceae
  • Genus: Conium
  • Species: C. maculatum

Hemlock (also known as “Poison Hemlock”) is a species of highly poisonous plant from the Apiaceae family (which includes carrots). Originally found in Europe and North Africa, Hemlock is now found worldwide in North and South America, Australia, and parts of Asia. The plant is widely regarded as one of the world’s most poisonous plants, and was used extensively in Ancient Greece for the purpose of executing prisoners who were condemned to death. This included Socrates, Phocion, and Theramenes.

Hemlock is often classified as a biennial flowering plant that grows upwards of 5 to 8 feet tall. Stems on the Hemlock are generally smooth and hollow, whereas leaves form a two to four pinnate that takes on a triangular shape. Flowers are typically small and white, with each flower possessing five petals. In regard to coloration, the Hemlock’s stems are green with reddish-purple streaks (or spots) covering the lower half of the stem’s base.

Signs and Symptoms of Hemlock Poisoning

Hemlock is an incredibly dangerous plant to humans and animals, alike. This is due to the plant’s numerous alkaloids that are present within all parts of the plant. Toxins within Hemlock are so dangerous that some individuals have even reported localized skin reactions from simply touching the plant’s leaves. Primary toxins within the Hemlock include coniine, N-methylconiine, conhydrine, g-coniceine, as well as pseudoconhydrine.

Upon ingestion of the plant, symptoms of Hemlock poisoning begin rapidly (as early as 30 minutes) as the alkaloids quickly begin to attack the body’s central nervous system. As with most poisonous substances, severity of symptoms generally depends on how much of the toxin has been ingested, as well as the overall toxicity of the Hemlock at its particular stage of growth. In severe cases, however, symptoms usually involve trembling, increased salivation, dilation of the pupils, muscle pain (and weakness), as well as rapid heart rate. As the poison continues to attack the body, muscle paralysis is common, along with convulsions and seizures, followed by unconsciousness (or coma). In its final stages, complete respiratory and kidney failure are common, along with acute rhabdomyolysis, and finally death.

Treatment

To date, no specific antidotes exist to combat the effects of Hemlock poisoning on the human body. As a result, treatment is usually centered around making the patient as comfortable as possible, while simultaneously treating individual symptoms as they appear. When breathing becomes impaired, intubation and ventilation may be used to open the individual’s airway. Gastric suction (stomach pumping) may also be used to remove traces of Hemlock from the gastrointestinal tract. Dialysis, anti-seizure medications, and intravenous fluids may also be utilized by doctors to protect the kidneys and brain, while also preventing dehydration from taking hold. In spite of these advancements in treatment options, fatality rates remain a staggering 30-percent in cases of severe poisoning.

Aconitum.

Aconitum.

8. Aconitum (Devil's Helmet)

  • Common Name(s): “Devil’s Helmet,” “Aconite,” “Wolf’s Bane,” “Queen of Poisons,” “Blue Rocket”
  • Binomial Name: Aconitum variegatum
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Order: Ranunculales
  • Family: Ranunculaceae
  • Genus: Aconitum
  • Species: 250+ Species Described

Aconitum (sometimes referred to as “Devil’s Helmet,” “Wolf’s Bane,” “Queen of Poisons,” or “Blue Rocket”) is a species of deadly plant from the Ranunculaceae family. Host to over 250 different species worldwide, the Aconitum is an herbaceous perennial plant that is endemic to the Northern Hemisphere. The plant is widely regarded as one of the most poisonous plants in the world, and can be found in mountainous meadows where the soil is well-draining and rich with nutrients.

Depending on the particular species, Aconitum tends to possess dark green leaves that are lobed with approximately 5 to 7 segments. These grow on a tall stem that is adorned by large blue, purple, pink, yellow, or white flowers. At peak growth, the plant tends to grow upwards of 3.3 feet (1 meter).

Signs and Symptoms of Aconitum Poisoning

Aconitum is considered an extremely deadly plant to humans and animals alike. All portions of the plant (including its roots) are known to contain highly-toxic alkaloids, along with potent neurotoxins, and cardiotoxins. Poisoning generally occurs from ingestion of the plant, with symptoms beginning almost immediately (or upwards of an hour). Initial symptoms include nausea, extreme vomiting, and diarrhea, followed by tingling and numbness of the mouth and face. Burning sensations in the abdomen are also common, and is usually followed by an inability to speak, hypotension (low blood pressure), and heart rhythm abnormalities (poison.org). Death is common within two to six hours, and is usually the result of complete paralysis of the respiratory system, or the onset of cardiac arrest. In cases of severe poisoning, however, some individuals have reportedly died within minutes of ingesting Aconitum.

Treatment

To date, no specific antidotes exist to combat Aconitum poisoning. As a result, treatment is typically centered around easing individual symptoms as they manifest themselves. If patients are able to receive rapid medical treatment, however, activated charcoal has proven relatively effective at neutralizing some of Aconitum’s toxins in the stomach. To be effective though, the charcoal must be administered within an hour of ingestion. This is usually followed by pain mitigation therapy, as well as the administration of intravenous fluids to maintain electrolyte balance in the body.

Due to Aconitum’s tendency to attack the heart and lungs, numerous drugs are often prescribed during hospitalization for maintaining proper heart rhythm. This is followed by intubation and ventilation when breathing becomes labored. In spite of these treatment options, however, fatality rates remain high. As a result, Aconitum should be always be avoided when possible.

Water Hemlock.

Water Hemlock.

7. Water Hemlock

  • Common Name: Water Hemlock
  • Binomial Name: Cicuta virosa
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Apiales
  • Family: Apiaceae
  • Subfamily: Apiodeae
  • Genus: Cicuta
  • Species: 4 Species Described

Cicuta (commonly referred to as “Water Hemlock”) is a species of highly-poisonous plant from the Apiaceae family. Commonly confused with Hemlock, Water Hemlock is actually a distinct species with a poison level that exceeds this close relative. The plant is found predominantly in North America and Europe, and typically grows in wet environments such as marshes, ponds, swamps, or streams (as its name implies). To date, it is one of the most toxic plants found in the United States.

Water Hemlock is classified as a perennial herbaceous plant, and is known to grow upwards of 8.2 feet (2.5 meters) at maturity. Stems on this species are both thick and hollow, with a purple-striped coloration. Branching off from the stem is a series of alternating leaves that reach upwards of 12 inches in length. This is followed by tiny leaflets that are sharply “toothed” and which reach upwards of 2 inches in diameter. Completing the Water Hemlock is a series of green or white flowers (that appear in spring or summer), along with tiny cylindrical fruit.

Signs and Symptoms of Water Hemlock Poisoning

The Water Hemlock possesses an extremely potent compound known as cicutoxin. This unsaturated aliphatic alcohol is found throughout all parts of the plant, with higher concentrations being found within the roots. Cicutoxin is extremely toxic to humans and animals alike, and is known to actively attack the body’s central nervous system. Symptoms usually begin within 15-minutes of ingestion, and involve severe nausea, vomiting, abdominal cramps, and tremors. This is often followed by muscle weakness, dizziness, lethargy, mental confusion, and recurring seizures. Seizures are perhaps the most significant issue faced with Water Hemlock poisoning, as their onset not only raises body temperature, but also results in brain swelling, hallucinations, and other neurological complications. Excess salivation, heart rhythm abnormalities, difficulties with breathing, as well as acute kidney failure are also common, with respiratory failure and ventricular fibrillation being the primary cause of death for most individuals.

Treatment

To date, no specific antidote exists to counteract the Water Hemlock’s poisonous effects on the human body. Treatment, therefore, tends to be centered around the alleviation of symptoms as they manifest themselves. If early treatment can be established, activated charcoal may be administered to help decontaminate toxins in the stomach. This is followed by anti-seizure medications, along with intubation and ventilation to support regular breathing. Intravenous fluids as well as dialysis may also be necessary for regulating blood pressure and heart rhythms, or to protect the kidneys from additional harm.

In spite of these treatment options, fatality rates for Water Hemlock poisoning continues to remain high for many. According to the Centers for Disease Control, several studies have shown fatality rates to be in the vicinity of 30-percent (cdc.gov). For these reasons, Water Hemlock should be avoided at all costs.

Oleander.

Oleander.

6. Oleander

  • Common Name: Oleander
  • Binomial Name: Nerium oleander
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Gentianales
  • Family: Apocynaceae
  • Subfamily: Apocynoideae
  • Genus: Nerium
  • Species: N. oleander

Nerium (commonly referred to as “Oleander”) is a species of highly-poisonous plant from the Apocynaceae family. Believed to have originated from the Mediterranean Basin, this toxic plant is now cultivated worldwide and can be found in most temperate or subtropical regions. To date, Oleander is often used extensively for landscaping and ornamental purposes due to its hardiness and natural beauty. It is also considered one of the deadliest plants in the world, with compounds that are extremely toxic to animals and humans alike.

Oleander is capable of taking on a shrub-like form, or can be cultivated to grow in the pattern of a small tree with a singular trunk at its base. They are also drought-resistant plants, but are generally incapable of tolerating long periods of frost. As a relatively fast-growing plant, the Oleander is capable of reaching upwards of 19.7 feet at maturity. They can be easily identified by their grayish bark, dark-green leaves (that are thick and leathery to the touch), as well as their clusters of flowers that vary between red, white, and pink. Oleander is also known to produce narrow fruit which contains numerous seeds.

Signs and Symptoms of Oleander Poisoning

Oleander possesses an extremely poisonous set of compounds known as oleandrin, which serve as cardiac glycosides when ingested by humans or animals. It is believed that all parts of the plant (including the roots) are toxic, and are even capable of causing severe skin irritation when individuals come into direct contact with its sap. Ingestion, however, remains the primary means for poisoning to occur.

Following ingestion, symptoms usually begin rapidly with gastrointestinal distress being among the first signs of poisoning. This includes extreme nausea, vomiting, excessive salivation, as well as abdominal cramps, and diarrhea (with blood). Oleander’s poisonous compounds are also known to affect the heart and central nervous system, leading to irregular heartbeat, tachycardia, and poor circulation. This is followed by drowsiness, tremors, and seizures which can lead to coma (and eventually death).

Treatment

Oleander poisoning is considered a life-threatening emergency that requires immediate hospitalization to prevent death. Standard treatment involves gastric lavage (stomach pumping) and induced vomiting to evacuate the stomach contents rapidly. This is followed by doses of activated charcoal which help to absorb the remaining toxins. In cases of severe poisoning, however, “Digoxin Immune Fab” is often administered as the antidote is extremely effective at disrupting the effects of oleandrin on the body. Temporary pacemakers may also be implemented to prevent heart rhythm abnormalities.

Fortunately, Oleander poisoning is relatively rare due to the plant’s extremely bitter and unpalatable taste (which often keeps individuals from consuming lethal doses). Nevertheless, experts warn that Oleander is extremely lethal in higher doses and should be avoided at all costs.

White Snakeroot.

White Snakeroot.

5. White Snakeroot

  • Common Name: White Snakeroot
  • Binomial Name: Ageratina altissima
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Asterales
  • Family: Asteraceae
  • Genus: Ageratina
  • Species: A. altissima

White Snakeroot (also known as “Richweed” and “White Sanicle”) is a species of poisonous plant from the Asteraceae family. Endemic to the eastern and central regions of North America, White Snakeroot is considered a perennial herb that is common in woodlands, brush thickets, and shaded areas. To date, it is considered one of the most dangerous plants in the world due to its potent toxins and potential for causing death in both humans and animals alike.

As an herb-like specimen, White Snakeroot is a relatively smaller plant that grows upwards of 4.9 feet at maturity. The plant tends to grow upright, and produces single or multi-stemmed “clumps” during the summer and early fall. Within these clumps are a series of fluffy white flowers that are surrounded by green leaves. For these reasons, White Snakeroot is often used for both landscapes and hedgerows by gardeners and yard experts.

Signs and Symptoms of White Snakeroot Poisoning

In spite of its natural beauty, White Snakeroot is extremely poisonous to humans and animals, with the capacity to cause extreme sickness or death. Nearly 80-percent of the plant is comprised of a toxin known as tremetol. When consumed, this deadly poison causes an effect known as “trembles” or “milk sickness” in individuals (or animals) that ingest any part of the plant. Although this type of poisoning is rare in the modern age, White Snakeroot poisoning resulted in several thousand deaths throughout the 1800s, and likely claimed the life of President Abraham Lincoln’s mother.

Due to its abundance in fields, ingestion of White Snakeroot often results from drinking milk from a cow that has accidentally consumed the plant (while grazing). In humans, symptoms of White Snakeroot poisoning often begin several hours after ingestion, and include abdominal cramps, trembling, vomiting, muscle weakness, and trouble standing. As the poison takes control of the body, convulsions and coma tend to follow, culminating in death if appropriate treatment is not sought immediately.

Treatment

To date, no specific treatment or antidote exists to counteract the effects of White Snakeroot. As a result, most treatment options are geared towards the treatment of symptoms as they appear. To combat tremetol poisoning, however, activated charcoal and gastric suction may be incorporated to rid the patient’s body of toxins. This is generally followed by intravenous fluids, pain mitigation therapy, and occasionally dialysis if the kidneys are compromised.

Fortunately, milk sickness from White Snakeroot is extremely rare in the present age. This is due to the fact that many farmers actively rid their fields of the plant in order to prevent cases of poisoning. In addition, milk is often collected and pooled together from an array of producers; thus, diluting any tremetol that may be present in the cow’s milk to a safe level (toxinology.com). Nevertheless, White Snakeroot is extremely dangerous, and should be avoided whenever possible.

Up-close photo of the Suicide Tree.

Up-close photo of the Suicide Tree.

4. Suicide Tree

  • Common Name: “Suicide Tree” or “Pong-Pong”
  • Binomial Name: Cerbera odollam
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Gentianales
  • Family: Apocynaceae
  • Genus: Cerbera
  • Species: C. odollam

Cerbera odollam (commonly referred to as the “Suicide Tree” or “Pong-Pong”) is a species of deadly plant from the Apocynaceae family. Endemic to India and Southern Asia, the Suicide Tree is a highly-toxic plant that is common in coastal swamps and marshes. To date, it is considered one of the most poisonous species of plant in the world due to its possession of a compound known as cerberin (located inside the kernels of its fruit). For centuries, kernels from the tree have been used extensively for both suicides and murderous intent (hence the plant’s sinister name).

The Suicide Tree bears a striking resemblance to Oleander, as they both derive from the same family of plants. On average, this species tends to grow upwards of approximately 20 to 50 feet (at maturity), and is known to produce thick green leaves, white flowers, as well as a mango-shaped fruit. Within this fruit is the tree’s deadly kernel. Measuring only 1.5 to 2 centimeters in diameter, these tiny kernels carry high concentrations of cerberin that is highly toxic to animals and humans when ingested (evergreen.edu).

Signs and Symptoms of Suicide Tree Poisoning

The Suicide Tree’s kernels are extremely lethal to humans due to its toxins that block calcium ion channels within the heart. The toxins are so powerful that a single kernel from the tree is considered lethal to humans nearly 100-percent of the time. Following ingestion of the kernel, symptoms generally begin rapidly with vomiting and abdominal cramps being among the most cited complaints from individuals. Difficulty breathing, migraine headaches, and a burning sensation within the mouth are also common issues. As the poison takes greater control of the body, however, these general symptoms are followed by heart rhythm abnormalities that become worse over time. Without treatment, individuals will eventually suffer coma, or cardiac arrest (leading to death).

Treatment

To date, no specific treatment exists to combat the effects of Suicide Tree poisoning. To complicate matters, cerberin is often extremely difficult to detect, making those who were victims of deliberate (or unintentional) poisoning difficult to treat in the early stages. As such, treatment of symptoms remains the primary course of action for most patients. However, in cases where poisoning is known to have occurred, doctors have discovered that cardiac pacing (pacemakers) are relatively effective at protecting the heart. This is often combined with activated charcoal, gastric suction, and the administration of intravenous fluids to maintain proper hydration and electrolyte balance.

In spite of these treatments, fatalities from Suicide Tree poisoning remain extremely high for patients. It is currently estimated that more than 500 individuals died from cerberin poisoning between the years 1989 and 1999 in India (evergreen.edu). This makes the Suicide Tree responsible for more deaths than shark-related attacks (worldwide) over the last few decades.

The deadly Rosary Pea.

The deadly Rosary Pea.

3. Rosary Pea

  • Common Name: “Rosary Pea” or “Jequirity Bean”
  • Binomial Name: Abrus precatorius
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Rosids
  • Order: Fabales
  • Family: Fabaceae
  • Genus: Abrus
  • Species: A. precatorius

The Rosary Pea (also known as “Abrus precatorius” or the “Jequirity Bean”) is a species of highly-poisonous plant from the Fabaceae family. Endemic to Australia and Asia, the Rosary Pea is now classified as an “invasive species” worldwide, as their introduction into temperate and tropical zones has resulted in devastating consequences for local plant life. Despite their use as an ornamental plant by many gardeners, this species is also considered one of the deadliest plants in the world due to their possession of a toxin known as abrin.

The Rosary Pea is considered an herbaceous flowering plant, as well as a perennial climber. The plant can be easily identified by their wood-like vine, slender branches, alternate-petaled leaves, as well as their small flowers that take on a white, violet, or pink coloration (ufl.edu). Rosary peas are also known to produce small seed pods that are approximately 1 to 2 inches in length. Within these pods is a series of 3 to 8 hard seeds that are bright red, shiny, and which possess a single black spot. Apart from the plant’s ornamental purposes, its seeds are used extensively for jewelry-making.

Signs and Symptoms of Rosary Pea Poisoning

Within the Rosary Pea’s seeds is a deadly substance known as abrin. Poisoning from abrin can occur through ingestion or inhalation of the plant’s seed particles, leading to a life-threatening emergency if medical treatment is not sought immediately. It is currently estimated that an abrin toxin dose of 0.00015% (per an individual’s body weight) will result in fatal poisoning (ufl.edu).

Depending on the exposure type (inhalation or ingestion), symptoms of abrin poisoning generally occur within 8 to 24 hours, and include difficulty breathing, fever, cough, nausea, bloody diarrhea, and hypotension (cdc.gov). Severe dehydration is also common, as the toxin tends to induce heavy sweating. In its final stages, hallucinations, bloody urine, and uncontrollable seizures occur, followed by a complete shutdown of the individual’s vital organs (such as the liver, spleen, or kidneys).

Treatment

Death from abrin exposure usually occurs within 36 to 72 hours of exposure. To date, no antidote exists to counteract the Rosary Pea’s deadly toxins. As a result, standard treatment for abrin exposure involves removing as much of the deadly toxin from the body as quickly as possible. As with many poisons, activated charcoal is often effective at absorbing portions of the toxin, but must be taken within an hour of ingestion. Gastric suction (stomach pumping) may also be employed, along with intravenous fluids to maintain electrolyte balance. This is generally followed by medications to treat specific symptoms, such as low blood pressure and seizures. In more severe cases, intubation and ventilation may also be required.

In spite of these treatment options, fatalities remain high for abrin poisoning. Fortunately, most cases of poisoning involve the ingestion of entire seeds. In these cases, the seed’s shell-casing tends to “insulate the toxin from absorption” within the digestive tract, preventing lethal exposure (nih.gov). Nevertheless, it is vital that animals and humans avoid exposure to these deadly seeds whenever possible.

Deadly Nightshade.

Deadly Nightshade.

2. Deadly Nightshade

  • Common Name: “Deadly Nightshade” or “Belladonna”
  • Binomial Name: Atropa belladonna
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Asterids
  • Order: Solanales
  • Family: Solanaceae
  • Genus: Atropa
  • Species: A. belladonna

Atropa belladonna (commonly referred to as “Deadly Nightshade” or “Belladonna”) is a species of highly-poisonous plant from the Solanaceae family. Originating in Europe and North Africa, the plant is now found worldwide in both temperate and subtropical regions. Despite its original purpose for medicine and cosmetics, the Deadly Nightshade is now considered an invasive weed species that is detrimental to local plant life. To date, this species is considered one of the most poisonous plants in the world due to its possession of tropane alkaloids. In its long history, the plant has been used extensively by humans as a deadly poison and agent for poison-tipped arrows.

The Deadly Nightshade is commonly found in limestone-rich soil that is both shady and moist. Generally classified as a branching herbaceous, this perennial species is known to grow upwards of 7-feet at maturity. It can be easily identified by its long, green leaves (7-inches in length), as well as bell-shaped flowers that take on a purplish-green coloration. Berries are also common on the Deadly Nightshade, and ripen to a shiny black hue (hence the plant’s name).

Signs and Symptoms of Deadly Nightshade Poisoning

The Deadly Nightshade contains a series of toxins known as tropane alkaloids. This includes atropine, hyoscine, hyoscyamine, as well as anticholinergic properties known to attack the body’s central nervous system. All parts of the plant are considered toxic to humans and animals, with the roots and leaves containing the greatest concentration of poison.

Following ingestion, symptoms usually begin rapidly and include dilated pupils, blurred vision, vertigo, migraine headache, and rash. This is generally followed by dry mouth, slurred speech, and tachycardia. As symptoms progress, the atropines present in the poison are known to disrupt the parasympathetic nervous system, resulting in hallucinations, confusion, and convulsions (nih.gov). Without treatment, coma, cardiac arrest, and eventually death result.

Treatment

Deadly Nightshade poisoning is a life-threatening emergency that requires immediate treatment for survival. In cases involving prompt treatment, one of the first lines of treatment involves activated charcoal to absorb the toxic agents remaining in the stomach. This is generally followed by intravenous fluids, as well as palliative care aimed at stabilizing the patient. In recent years, an anticholinesterase known as physostigmine has also shown promising results against poisoning as it acts as a cholinesterase inhibitor (nih.gov).

In spite of these treatment options, fatality rates remain high for nightshade poisoning as the ingestion of only two berries is capable of causing death to a human adult. As such, this is a plant that should be avoided at all costs.

The Castor Bean Plant (world's deadliest and most poisonous plant).

The Castor Bean Plant (world's deadliest and most poisonous plant).

1. Castor Bean Plant

  • Common Name: Castor Bean Plant
  • Binomial Name: Ricinus communis
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Rosids
  • Order: Malpighiales
  • Family: Euphorbiaceae
  • Genus: Ricinus
  • Species: R. communis

Ricinus communis (commonly referred to as the “Castor Bean Plant” or “Castor Oil Plant”) is a species of extremely poisonous plant from the Euphorbiaceae family. Originating in Eastern Africa, the Mediterranean, and parts of India, the Castor Bean Plant is now found worldwide and is a favorite for landscaping and ornamental purposes. In spite of its popularity, this species is widely considered the deadliest plant in the world due to the presence of ricin within its beans. Consumption of these beans is considered life-threatening unless treated, as ricin is highly-toxic to both animals and humans.

The Castor Bean Plant is classified as a perennial flowering shrub. It is fast-growing, and capable of reaching upwards of 40-feet at maturity. The plant can be easily identified by onlookers due to its long, green, and glossy leaves (that are 6 to 18 inches long), as well as its spherical stems and flowers that are yellowish-green or red (depending on the species). Fruit is also common near the leaves, and takes the form of a reddish-purple capsule that surrounds a shiny, bean-shaped seed.

Signs and Symptoms of Ricin Poisoning

The Castor Bean Plant’s seeds contain a deadly toxin known as ricin. This substance is known as a carbohydrate-binding protein that inhibits protein synthesis (nih.gov). As a result, ricin is extremely deadly when inhaled, ingested, or injected into the bloodstream, as it wreaks havoc on the body’s central nervous system. Current estimates suggest that a lethal dose for humans is only 4 to 8 seeds (beans).

Symptoms of ricin poisoning vary (depending on the exposure type). Nevertheless, most symptoms usually appear within 2 to 4 hours, and include burning sensation of the mouth and throat, abdominal cramps, bloody diarrhea, and hypotension. This is followed by a decrease in urine output, as well as the vomiting of blood which leads to hypovolemia (low blood volume). This, in turn, often results in shock, causing organ failure in the kidneys, liver, and pancreas. Without treatment, death is common in nearly 100-percent of cases.

Treatment

To date, no specific treatment or antidote is available to combat the effects of ricin poisoning. Treatment, therefore, is non-specific and generally focuses on minimizing the effects of the poison on the body while simultaneously managing symptoms as they appear. When administered rapidly, activated charcoal is often effective at absorbing ricin toxins within the stomach, whereas gastric lavage is utilized to clean out the upper gastrointestinal tract. Intravenous fluids may also be incorporated into treatment regimens, followed by airway management and assisted ventilation (when breathing becomes labored). In extreme cases, dialysis may also be necessary to mitigate the effects of the toxins on the kidneys.

Despite these treatments, fatality rates remain extremely high for ricin poisoning with death occurring 4 to 72 hours after exposure. And while some individuals manage to survive its effects, long-term complications are common, with organ damage (or failure) developing in the majority of cases. For these reasons, the Castor Bean Plant is easily the deadliest plant in the world.

Field of tobacco plants.

Field of tobacco plants.

Honorable Mention: Tobacco

  • Binomial Name: Nicotiana tabacum
  • Geographical Range: Worldwide Distribution

Although tobacco failed to make the “top 10” deadliest plants, it deserves special attention due to its use in cigarettes and other tobacco-based products. According to the CDC, smoking results in more than 480,000 deaths per year (in the United States alone). This equates to an average of 1,300 deaths per day (cdc.gov). Thus, in some ways, tobacco is actually deadlier than the Castor Bean Plant due to the number of illnesses and cancer-causing agents that are found within its toxins.

Works Cited

Articles:

Images:

Wikimedia Commons.

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2020 Larry Slawson

Comments

Jacob on September 17, 2020:

Nice article. By the way, I would like to tell you that Jesus loves you. May God bless you abundantly

Danny from India on September 17, 2020:

Some plants are deceptively tricky. It's better to research before picking any.:)

Pamela Oglesby from Sunny Florida on September 16, 2020:

Oleander and Jimson Weed have pretty flowers but I don't want to be near them. I think I have read mysteries where Hemlock was used to poison someone. Your just can't be too careful even when the plants look harmless or pretty.

This is an excellent very informative article, Larry.

Larry Slawson (author) from North Carolina on September 16, 2020:

Thank you, Ivana! I'm so glad you enjoyed!

Ivana Divac from Serbia on September 16, 2020:

Such a well-written and informative article. This was a very interesting read.