Here are the 18 Scariest Plants in the World.

1. Gympie-Gympie (Dendrocnide Moroides)


Gympie-Gympie is a large shrub native to rainforest areas in the northern half of eastern Australia and Indonesia. It is best known for stinging hairs that cover the whole plant and deliver a potent neurotoxin when touched. It is the most toxic of the Australian species of stinging trees.

Contact with the leaves or twigs causes the hollow, silica-tipped hairs to penetrate the skin. The hairs cause an extremely painful stinging sensation that can last for days, weeks, or months, and the injured area becomes covered with small, red spots joining together to form a red, swollen welt. The sting is infamously agonizing. Ernie Rider who was slapped in the face and torso with the foliage in 1963 said, “For two or three days the pain was almost unbearable; I couldn’t work or sleep, then it was pretty bad pain for another fortnight or so. The stinging persisted for two years and recurred every time I had a cold shower. … There’s nothing to rival it; it’s ten times worse than anything else.”

In 1994, an Australian ex-serviceman named Cyril Bromley used its leaf as a toilet paper by accident and he went on to kill himself because the pain was too strong.

2. Manchineel Tree (Hippomane mancinella)

Manchineel Tree

This flowering plant is native to tropical southern North America and northern South America. Its fruit and leaves resemble an apple tree. Its present-day Spanish name is in fact manzanilla de la Muerte, “little apple of death.”

All parts of the tree contain strong toxins, some unidentified. Its milky white sap contains phorbol and other skin irritants, producing strong allergic dermatitis. Standing beneath the tree during rain will cause blistering of the skin from mere contact with this liquid (even a small drop of rain with the milky substance in it will cause the skin to blister). The sap has also been known to damage the paint on cars. Burning the tree may cause ocular injuries if the smoke reaches the eyes. Eye contact with its milky sap can cause blindness.

The fruit is possibly fatal if eaten. When ingested, the fruit is reportedly “pleasantly sweet” at first, with a subsequent “strange peppery feeling …, gradually progress[ing] to a burning, tearing sensation and tightness of the throat”. Symptoms continue to worsen until the patient can “barely swallow solid food because of the excruciating pain and the feeling of a huge obstructing pharyngeal lump.”

The tree is recorded as the world’s most dangerous tree by the Guinness World Records.

3. Castor Oil Plant, (Ricinus communis)

Castor Oil Plant

This plant is usually grown for the castor oil. As quite a strong laxative, castor oil can be the cause of harm, especially if it is ingested accidentally as a result of spray from its use as a lubricant, but it is the substance left in the residue after the beans have been crushed to produce the oil which makes Ricinus communis such a notorious plant. Because those residues contain ricin. Ricin, a simple protein, is believed to be one of the most toxic naturally occurring substances and is often mentioned as a potential terrorist weapon for causing mass murder in spite of all evidence to the contrary.

If ingested, it causes vomiting which in many cases expels the poison and prevents death. If injected or in some case if its smoke is inhaled it causes stomach pain, dehydration and destroys the main internal organs.

4. Jimson Weed or Loco Weed (Datura stramonium)

Jimson Weed

Its flowers are known as Hell’s snare or devil’s trumpet. The plant is a member of the nightshade family. Its better-known relatives include eggplant, tomatoes, peppers, and tobacco. Datura and other nightshades contain a lot of nasty alkaloids. “Jimson weed” is notorious among ranchers and farmers, as cows and horses which eat this plant tend to end up very sick or dead. Human toxicity is also well-known. Scopolamine a.k.a the South American “zombie drug” used to make unsuspecting victims totally compliant to their attackers’ every demand, comes from Datura and its relatives.

The crazy part is that some people intentionally eat the datura plant in order to get high. Used in this way, the plant is most accurately classified as a deliriant. This isn’t like LSD, shrooms, weed, ketamine, etc. where in most situations and with responsible usage you are mostly aware that you are high and you’ve taken drugs. One key feature of deliriants is that you have no idea that you’ve completely lost touch with reality. The trip is similar to schizophrenia or dementia: horrifying multi-layered fantasies filled with bizarre nonsensical events, like Inception directed by David Lynch.

Symptoms of datura toxicity include:

  • Heart palpitations, sensitivity to light.
  • Extremely dry mouth and difficulty urinating.
  • Visual and tactile hallucinations: shadows, abstract lines, and shapes, spiders, wasps, transparent insects and animals. One particular recurring theme among users of deliriants includes seeing “shadow beings”, like spirits from another realm.
  • Being unable to distinguish reality from fantasy: losing all idea of time, thinking you are doing things when you’re not, not realizing you’re doing things when you are.
  • Pronounced amnesia is another commonly reported effect.

5. Water Hemlock (Cicuta)

Water Hemlock

When I was a kid my mother made me learn the difference between Queen Anne’s Lace and water hemlock. Because the most common one, Queen Anne’s Lace, is a really pretty flower that is a beneficial weed, and you could even eat it if you were lost in the woods. The other, water hemlock, also grows everywhere and looks very similar, but is highly poisonous.

Upon consumption, both in humans and other species, the symptoms of poisoning are mainly characterized by generalized seizures followed by swelling in the brain, blood coagulation disorders, muscle breakdown, and kidney failure, hallucinations, delirium, dilated pupils, coma. Deaths usually occur from respiratory failure.

6. Doll’s-Eyes (Actaea pachypoda)

Actaea pachypoda

Its most striking feature is its fruit, a 1 cm diameter white berry, whose size, shape, and black stigma scar give the species its common name, “doll’s eyes.” Both the berries and the entire plant are considered poisonous to humans. The berries contain cardiogenic toxins which can have an immediate sedative effect on human cardiac muscle tissue, and are the most poisonous part of the plant. Ingestion of the berries can lead to cardiac arrest and death.

7. Giant Hogweed (Heracleum mantegazzianum)

Giant Hogweed

Giant hogweed is a member of the carrot/parsnip family and resembles cow parsnip quite strongly. It’s a very tall plant with a crown of clustered white flowers. More dangerously, it looks like a really big version of Queen Anne’s Lace, which is an utterly innocuous flower. Do not let your small children around giant hogweed.

The problem with giant hogweed lies in the furanocoumarin, a phototoxic compound in the sap that can transfer when a person touches the plant. It gets into the nucleus of a person’s skin cells and bonds straight with the DNA. The cells die, and they don’t exactly go gentle.

Signs of hogweed contacts begin with a red rash and itching in the contacted area, which blossoms over 48 hours into intensely painful, burning, raised blisters. The sting just keeps going for months, and even when it’s gone, it leaves a nice, purple scar for you to remember it by. Because it’s phototoxic, contact with sunlight worsens the reaction. Furthermore, because the compound is unnoticeable at first, it’s hilariously easy to get it on your hands and then rub your eyes. The blindness is usually temporary.

This plant is biennial, invasive, and easily pops up in peoples’ backyards. Since it looks innocuous – fairly beautiful, in fact – it often goes under the radar just long enough to injure people.

8. Monkshood (Aconitum Napellus)


The monkshood plant is an herbaceous wildflower that can be found growing in mountain meadows throughout the northern hemisphere. The plant gets its name from the shape of the posterior sepal of the flowers, which resembles the cowls worn by monks. Also known as wolfsbane and Aconitum, monkshood has become popular as a garden addition because of its purple/blue flowers and attractive foliage.

All members of the genus Aconitum, monkshood included, are poisonous. In fact, wolfsbane, that other common name, came about from using the ground root of perennial monkshood in meaty bait to kill the once hated animals. It should never be grown within reach of children or pets and all parts of the plant are toxic, including the sap. Mere brushing against its flowers may lead to death. Death usually occurs within two to six hours in fatal poisoning. The initial signs are gastrointestinal including nausea, vomiting, and diarrhea. The main causes of death are ventricular arrhythmias and paralysis of the heart or of the respiratory center.

9. Pokeweed (Phytolacca americana)


It grows up to 8 feet in height and is native to the eastern United States and has significant toxicity.

The flowers are green to white, followed by purple to almost black berries which are highly poisonous and children especially seem to be attracted to the berries.

10. Rosary Pea (Abrus precatorius)

Rosary Pea

Abrus precatorius contains toxic lectin, or toxalbumin, abrin. Abrin is similar in structure to ricin. It is often described as deadly and some newspapers have claimed that it is twice as toxic as ricin. Occasionally, rosary pea and castor bean get confused and the impression is given that they are the same thing.

The plant is best known for its seeds, which are used as beads and in percussion instruments, and which are toxic because of the presence of abrin. There are persistent reports that the workers who pierce the seeds in order to thread them can suffer poisoning or even death from a pinprick, but there seems to be little evidence. An online search found 265 scientific papers referring to Abrus precatorius but not one of them dealt with occupational poisoning.

The plant is native to India and grows in tropical and subtropical areas of the world. Symptoms of poisoning include nausea, vomiting, convulsions, liver failure, and death, usually after several days. The seeds are also used as beads in jewelry, which is probably unwise, mainly because young children are unfortunately drawn to the attractive beans and may suck or chew on them.

11. The Sandbox Tree (Hura crepitans)

The Sandbox Tree

This evergreen tree is native to tropical regions of North and South America including the Amazon Rainforest. It is recognized by the many dark, pointed spines and smooth brown bark. These spines have caused it to be called Monkey no-climb. It oozes a sap that is caustic (similar to drain cleaner). Fishermen have been said to use the sap from this tree to poison fish. Indigenous tribes have used arrow poison from its sap. The whole tree is also covered in spikes. Its seed pods are fist-sized fruit that, when ripe, explode with such force that they routinely wound nearby people and livestock, which is unsurprising when you look at the shrapnel they put out.

12. The Devil’s Breath (Flowers of Brugmansia)

This plant’s large, fragrant flowers give them their common name of angel’s trumpets or the devil’s breath. All parts of Brugmansia are poisonous, with the seeds and leaves being especially dangerous.

Brugmansia are rich in Scopolamine (hyoscine), hyoscyamine, and several other tropane alkaloids. Effects of ingestion can include paralysis of smooth muscles, confusion, tachycardia, dry mouth, diarrhea, migraine headaches, visual and auditory hallucinations, mydriasis, rapid onset cycloplegia, and death.

Brugmansia induces a powerful trance with violent and unpleasant effects, sickening aftereffects, and at times temporary insanity. These hallucinations are often characterized by complete loss of awareness that one is hallucinating, disconnection from reality, and amnesia of the episode, such as one example reported in Psychiatry and Clinical Neuroscience of a young man who amputated his own penis and tongue after drinking only 1 cup of Brugmansia tea.

Scopolamine is used in places like Columbia to turn tourists into unwitting zombies that empty out their bank accounts and have no recollection of the events. The scammers blow it into your face.

13. Deadly Nightshade (Atropa Belladonna)

Atropa Belladonna

Belladonna is one of the most toxic plants found in the Eastern Hemisphere. The foliage and berries are extremely toxic. Berries are green, ripening to a shiny-black. 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. Ingestion of a single leaf of the plant can be fatal to an adult.

The symptoms of belladonna poisoning include dilated pupils, sensitivity to light, blurred vision, tachycardia, loss of balance, staggering, headache, rash, flushing, severely dry mouth and throat, slurred speech, urinary retention, constipation, confusion, hallucinations, delirium, and convulsions.

Drops prepared from the belladonna plant were used to dilate women’s pupils, an effect considered to be attractive and seductive.

14. Coyotillo Bush (Karwinskia Humboldtiana)

Coyotillo Bush

The coyotillo bush is a little-known shrub that grows along the Mexico/Texas border. The small, greenish flowers produce a green fruit that ripens to a dark purple-black color. The small (about 1/2-inch) globular fruit is attractive, has a sweet juicy pulp when ripe. The berries however once ingested cause irreversible paralysis 8 hours after ingestion. Ingestion of the fruit, especially by children, is a common source of poisoning in rural northern Mexico. The poisoning manifests itself as ascending paralysis, starting in the extremities and moving toward the trunk, and in extreme cases, victims need mechanical assistance to breathe. Although many victims recover completely, in serious cases they are left a quadriplegic.

15. Sago Palm (Cycas Revoluta)

Sago Palm

Sago palm is native to southern Japan. The plant is extremely poisonous to animals (including humans) if ingested. Pets are at particular risk since they seem to find the plant very palatable. Clinical symptoms of ingestion will develop within 12 hours, and may include vomiting, diarrhea, weakness, seizures, and liver failure. The pet may appear bruised, have nose bleeds, blood in the stool, bloody straining, and blood in the joints. The ASPCA Animal Poison Control Center estimates a fatality rate of 50 to 75% when ingestion of the sago palm is involved. If any quantity of the plant is ingested, a poison control center or doctor should be contacted immediately. Effects of ingestion can include permanent internal damage and death.

All parts of the plant are toxic; however, the seeds contain the highest level of the toxin cycasin.

16. Nerium Oleander

Nerium Oleander

It’s grown all over California (even in schools) for its really pretty flowers which range from deep pink to white. The seeds in the flower are among the most poisonous in the world if ingested, and antidotes are few. Chances are, if you live anywhere on the West Coast or in Southern Asia, (yellow variants are common there) you’ve seen this plant and paid it no attention. It is one of the most poisonous of commonly grown garden plants. Dogs and humans are relatively sensitive to its toxins.

Ingestion of this plant can affect the gastrointestinal system, the heart, and the central nervous system. The gastrointestinal effects can consist of nausea and vomiting, excess salivation, abdominal pain, diarrhea that may contain blood, and especially in horses, colic. Cardiac reactions consist of irregular heart rate, sometimes characterized by a racing heart at first that then slows to below normal further along in the reaction. Extremities may become pale and cold due to poor or irregular circulation. The effect on the central nervous system may show itself in symptoms such as drowsiness, tremors or shaking of the muscles, seizures, collapse, and even coma that can lead to death.

17. Mandrake (Mandragora Officinarum)


Mandrake is limited to small areas of northern Italy, the coast of former Yugoslavia, and around the Mediterranean. Because mandrakes contain deliriant hallucinogenic tropane alkaloids and the shape of their roots often resembles human figures, they have been associated with a variety of superstitious practices throughout history.

The alkaloids make the plant, in particular the root and leaves, poisonous, via anticholinergic, hallucinogenic, and hypnotic effects. Anticholinergic properties can lead to asphyxiation. Ingesting mandrake root is likely to have other adverse effects such as vomiting and diarrhea. Clinical reports of the effects of consumption include severe symptoms similar to those of atropine poisoning, including blurred vision, dilation of the pupils, dryness of the mouth, difficulty in urinating, dizziness, headache, vomiting, blushing, and a rapid heart rate (tachycardia). Hyperactivity and hallucinations also occurred in the majority of patients.

18. Cerbera Odollam (Suicide Tree)

Cerbera Odollam

Cerbera odollam a.k.a. the “Suicide Tree,” grows in the swamp and marshy areas of India and southern Asia. Going by the common name “Pong-pong” and growing upwards of 30 feet (~10 meters) tall, it has fruit that looks like a small, green, mango that covers an oval-shaped kernel which is just the seed inside the nut or pit of fruiting plants.

The Cerbera kernel contains several glycosides, with the most notable being cerberin. The moniker “Suicide Tree” is well earned. In a ten-year study in the Kerala state of India, Cerbera odollam was responsible for 537 poisonings, half of all plant poisoning cases. The most popular use though is a suicide, most likely because it is widely available and its lethality is well known. In these cases the individuals remove the kernel from the fibrous seed husk and mash it with cane sugar, making a sweet, albeit deadly, treat.

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Last Update: February 24, 2021