Plants have fascinated people since the dawn of time, with many plants used for both medicinal and spiritual practices. However, not all plants present pretty flowers and scents that invite you for a closer look. People have used deadly plants throughout history for medicine and to cause pain and even the death of another. Here we highlight 10 most dangerous plants in the world.
Nature has always been a source of beauty and terror. From its serene landscapes to its deadliest creatures, the natural world can evoke a wide range of emotions. But have you ever thought about the potential dangers hiding in plain sight, in your own backyard? The plants that you admire for their vibrant colours and intricate shapes could be some of the 10 most poisonous plants harbouring a sinister secret. They could be toxic.
Some garden plants may pose a threat to your family. So, we dug into the natural world of poisonous plants and found 10 most dangerous plants with the potential to cause serious harm, even death.
- Belladonna
- Aconitum
- Castor Bean
- Datura
- Hemlock
- Euphorbia
- Oleander
- Rhubarb
- Tobacco
- Daphne
Plants typically have defence mechanisms to protect them from being eliminated by herbivores and insects, but many species take it to the extreme to ensure their survival. This is our list of 10 most dangerous plants.
So, whether you have green fingers, are looking to expand your knowledge, or are simply curious about the hidden dangers in your backyard, read on. There are also poisonous fungi to avoid. Find out more about those dangers and these 10 most poisonous plants we discovered.
Disclaimer: The medical information in this article is provided as an information and entertainment resource only, and is not to be used or relied on for any diagnostic or treatment purposes. This information should not be used as a substitute for professional diagnosis and treatment.
Atropa Belladonna (Deadly Nightshade)
Belladonna is a poisonous plant that is native to parts of Asia and Europe. It is also known as deadly nightshade. The nightshade family, which includes tomatoes, potatoes, aubergines, atropa, and datura, is known for its intimidating line-up of toxic plants.
Belladonna produces small, black berries that must not be eaten. Eating them, or even the leaves of a belladonna, can be fatal. Just like poison ivy, a person whose skin comes into direct contact with the leaves may develop a rash.
Belladonna’s poison is extremely potent, and in ancient times, people used ita for its toxic properties as an oral poison and on the tips of arrows. 10 bays is enough to kill an adult, and 2-3 bays is deadly to children, according to research.
Deadly Nightshade is sold as an over-the-counter supplement. Small doses of the plant can help cure common ailments like fever, motion sickness, and flu, but it is generally not safe to consume. Belladonna poisoning can trigger severe seizures, rashes, hallucinations, an inability to sweat or urinate, convulsions, and even comas. If a high dosage of belladonna is consumed, it may be fatal.
So, what can you do in circumstance where someone has belladonna poisoning? Well, the antidote is physostigmine, which is the same as for atropine. Physostigmine crosses the blood-brain barrier and reversibly inhibits anticholinesterase. Benzodiazepines are also frequently used for sedation to control belladonna’s milder effects, including delirium and agitation.
Of all the plants on this list, the deadly nightshade is possibly one of the most familiar plants that can kill you. It has been used throughout history to eliminate enemies and has caused the tragic death of children drawn to its sweet purplish-black berries. While all parts of the plant are poisonous when ingested, many people succumb to the toxins from eating the berries.
Ingestion of Deadly Nightshade reveals several symptoms of poisoning, including:
- Rapid heart rate (tachycardia)
- Delirium, and
- Respiratory failure.
These symptoms may often lead to death, depending on the amount the victim ingested. Even when the plant is handled, the toxins can be absorbed into the skin, causing severe dermatitis. Even with its poisonous properties, some still use the plant for medicinal purposes, which is not recommended.
Check out this video on deadly nightshade, explaining why it’s one of the most dangerous plants in the world with some historical information.
Aconitum (Monkshood)
Aconitum – commonly referred to as monkshood, aconite, wolf’s bane, queen of poisons, or blue rocket – is a genus of over 250 species of violet flowering plants across North America, Europe, and Asia. They thrive in the moist soils of meadows and lush mountainsides.
Many aconitums are labelled as extremely poisonous, even to touch. Why? Because they contain high amounts of toxic aconitine and alkaloids, which are primarily stored in their roots and tubers; they protect themselves through a blend of neurotoxin and cardiotoxin.
It only takes 1 gram of raw aconite plant to have a lethal effect on the consumer. Symptoms appear no later than one hour upon contact or ingestion, with fatalities occurring almost immediately after eating.
Signs of aconitum poisoning include, but are not limited to, a burning sensation in the abdomen, hypotension, nausea, weakness, and heart arrhythmias. When it comes to treatment, patients require both close monitoring of their blood pressure and their cardiac rhythm.
In milder cases, activated charcoal may be provided as a treatment within one hour of consumption. For more severe cases, prescriptions include lidocaine, amiodarone, and bretylium – or, if none of these medications take effect, a cardiopulmonary bypass may be performed.
During the Middle Ages, witches supposedly used aconitum in their flying and love potions because of the feelings of dizziness and numbness brought on by its irregular heartbeat side effects. Due to these poisons often being fatal for the recipient who drank them, the plant also earned the name of Mourning Widow.
Notes: The name wolf’s bane came from Europeans using it to lace meat to poison large carnivores, creating havoc. Sorry to disappoint you if you thought you could use it to protect you against werewolves, as modern books and TV shows have suggested.
Aconitine is the chemical causing illness and death, most concentrated in the plant root system and seeds. This toxin creates a chain reaction that will eventually stop your heart. However, some people still use wolf’s bane for medicinal purposes, such as in Chinese medicine.
Castor bean (Ricinus communis)
There is no known antidote to cure the poisoning from this plant, and death usually follows the painful symptoms.
The castor bean plant is well known for creating castor oil. But did you know the Guinness Book of World Records has dubbed it as the most deadly plant in the world? Based on the amount it takes to kill a human, the castor bean tops the list of the world’s 10 most dangerous plants.
The castor bean plant is rich in ricin: a biochemical compound so potent it has also been classified as a weapon.
Because of its unassuming appearance, it is often mistaken for a fern. If an adult consumes 4-8 of the spine-coated beans, they have taken a potentially lethal dose; irritation begins immediately in the form of a burning in the mouth or throat, sudden parchedness, difficulty breathing, fever, and bloody diarrhoea.
As symptoms progress – generally 12 to 48 hours after consumption – these symptoms are likely to worsen, resulting in convulsions and a loss of consciousness. These can precede death, as there is no specific treatment for castor bean plant poisoning.
Other than through the direct consumption of castor beans (which is unlikely, since they are usually exclusive to farms and used to make castor oil), ricin must be intentionally prepared in order to truly poison someone.
When the naturally occurring poison ricin is consumed, inhaled, or injected, it can cause severe illness or death. Ricin is highly toxic, causing symptoms such as:
Hallucinations
Seizures
Bloody urine and stool
Organ failure.
There is no known antidote to cure the poisoning from this plant, and death usually follows the painful symptoms.
Datura Stramonium (Jimsonweed)
Datura (also known as Jimsonweed) is a delicate, unassuming white flower with trumpet-shaped petals. It is part of the nightshade family, so be wary of approaching this pretty perennial. It has been dubbed The Devil’s Trumpet for good reason.
All species of Datura are deemed poisonous, as well as psychoactive. In fact, their seeds can trigger respiratory depression, heart arrhythmias, delirium, hallucinations, psychosis, and, if consumed, death. But despite its high levels of toxicity, it has been used throughout history to induce hallucinations. This has long tied it to groups associated with witchcraft and sorcery.
It has also earned a reputation as roadside poison. Thieves looking to rob strangers have been known to offer unsuspecting travellers treats. One small extract of the delirium-inducing plant mixed with cookies, wine, or cigarettes, can render the victim incapable of resistance.
From the 45 fatalities recorded between 1983–2009, the Datura species of plant was responsible for 20% of all fatal outcomes, making it the leading cause of death attributed to plant exposures during that time.
Just half a teaspoon of datura seed is enough to be lethal to an adult. In the case of Datura poisoning, physostigmine, a cholinesterase inhibitor, may be used to reverse toxicity. Physostigmine can be given intravenously to an adult in a dose of 0.5–2.0 milligrams at a rate of no more than 1 mg per minute, with a second dose being administered if necessary.
Some Native American tribes are reported to have used Datura for its psychoactive properties. From 1990-2000, there were recorded incidents of adolescents smoking or ingesting Datura, which resulted in a number of early deaths.
Jimsonweed has many nicknames, including the most common ‘moonflower’ and ‘devil’s trumpet’. Even though this plant is toxic, some people use the leaves as medicine to treat respiratory illnesses and nerve diseases. Harvesting this plant for medicinal purposes is not recommended for the following reason.
Within 60 minutes of ingesting this plant, you may experience symptoms like:
- Hallucinations
- Thirst
- Dilated pupils
- Blurred vision
- Difficulty speaking
- Difficulty swallowing
- Rapid heart rate (tachycardia).
Hemlock (Conium maculatum)
Although its burst of dainty white flowers may look harmless, hemlock is anything but. Just 6-8 leaves of this plant can prove fatal to the consumer.
Easily earning a spot on the list of 10 most poisonous plants in the world, the ingestion of as little as two centimetres of hemlock root can be fatal in adults. Even touching its flowers or leaves can make you seriously ill.
Accidental ingestion of hemlock may result in central nervous system depression, respiratory failure, acute rhabdomyolysis, acute renal failure, and, in some unfortunate circumstances, death. The main treatment of hemlock poisoning is supportive care under the watchful eye of a professional.
This is especially true for children, as hemlock poisoning is more acute for their smaller bodies.
Toxicity from the hemlock plant occurs after ingesting any part of the plant, including the seeds. The alkaloids it contains can prove fatal in small amounts, causing respiratory failure. Accidental poisoning typically happens because of mistaken identity because it looks similar to wild parsnips or parsley.
Hemlock is another plant that has been used and abused throughout history and still makes the list as one of the world’s 10 most dangerous plants.
Euphorbia (Spurge)
Frequently found flowering in gardens across the United Kingdom, euphorbia is labelled as poisonous and a skin and eye irritant by the Royal Horticultural Society. Its white, milky sap was initially developed as a way to ward off herbivores, but gardeners everywhere are finding it an unexpected eye and skin irritant throughout the spring and summer.
If you get sap on your skin, you should wash the area thoroughly with soap and water. If the sap becomes congealed on the skin, it’s no longer soluble in water and should instead be removed with minimal scrubbing with soap or milk.
Those who do not quickly rinse their eyes, however, will experience:
- Bloodshot eyes
- Gritty, itchy eyes
- Watering eyes
- General skin irritation
It’s recommended to always wear eye and hand protection when gardening near euphorbia.
Oleander (Nerium)
The Oleander is a gorgeous flower-producing shrub that has been around since ancient times. Today it is commonly used for ornamental purposes. But don’t let its beauty fool you because this plant can kill a human with just one leaf. All parts of the oleander are toxic when ingested, and you can also experience skin irritation by brushing up against its foliage.
It is one of the most common ornamental evergreen shrubs across both Europe and North America… but did you know that a single leaf can kill an adult if consumed, making it one of the most poisonous plants in the world?
All parts of the plant are poisonous when eaten, even if the leaves are dry or the shrub is dormant. In fact, the smoke created by burning the dry branches or other shrub debris can also cause a toxic reaction in your airways or your whole system.
If consumed, death can come by way of the oleander’s neurotoxins slowing the heart to the point of lapsing into a coma, followed by death. Additionally, its high rate of toxicity may result in severe disorientation, seizures, and collapse.
If poisoned by oleander, healthcare professionals will likely pump your stomach (also known as a gastric lavage) and implement breathing support while they run blood and urine tests. From there, treatment is dependent on the quantity of oleander consumed. However, specific symptoms and treatment of oleander poisoning will vary greatly on a case-by-case basis.
Rhubarb
When you think of rhubarb, do you think of stewed rhubarb and custard and rhubarb tart, or garnishes on seasonal drinks?
You may be surprised to learn that rhubarb’s leaves hold potent amounts of poison. There’s nothing sweet about them.
Rhubarb leaves are considered inedible due to their high concentration of what is called oxalic acid. And both the stalks and leaves contain it. Too much oxalate in the body can lead to a condition known as hyperoxaluria, which is when excess oxalate is excreted in the urine. This leads to the formation of kidney stones which, if left untreated, can trigger kidney failure.
While rhubarb poisoning is exceedingly rare, and you would need to consume a few kilograms of leaves to reach a lethal dose, it is recommended to call your local healthcare line immediately to request an ambulance for an affected person.
Tobacco
The Tobacco plant was once touted for its supposed mental and physical health benefits, even going so far as to be recommended by doctors. This is no longer the case; tobacco is proven to be a toxic and destructive plant if consumed in any form.
While we all know nicotine isn’t good for you, the tobacco plant itself holds significant amounts of toxicity. Cultivated tobacco is rich in nicotine. Ingesting its leaves, stems, and flowers can result in severe nicotine poisoning or tobacco sickness.
Nicotine binds to specific receptors in your body, found throughout your nervous system. Ingesting large amounts of nicotine can cause a range of symptoms. These symptoms include:
- Muscle paralysis or seizures
- Abdominal cramps
- Vomiting
- Changes in blood pressure or heart rate
- Coma
- And death
If skin or eyes have come in contact with nicotine, rinsing them with warm water for 15 minutes may help minimise burning. Symptoms can last one to two hours if you’ve had mild exposure to a tobacco plant. If you’ve had severe exposure, symptoms can last up to 18 to 24 hours after exposure.
The lethal consumption of tobacco leaves is roughly 30-60mg of nicotine, equivalent to eating around half of a standard tobacco pouch. To counteract tobacco plant poisoning, patients are generally provided artificial respiration and oxygen therapy.
Acute tobacco plant poisoning most commonly occurs in pets and children who have come into accidental contact with the plant. Activated charcoal, a chest X-ray, and ECG, an IV, laxatives, or anti-seizure medications may all be implemented to help the patient make a full recovery.
How well a person or animal recovers depends on the amount of poison swallowed and how quickly treatment is received. The faster one gets medical help, the better the chance of a full recovery.
Daphne
As a flowering shrub identified through its bright red or black berries, all parts of this beautiful plant are poisonous. Even contact with its sap can trigger blistering and rashes.
There are actually over 70 species of shrub within the Daphne family. Each has its own level of toxicity, but one thing is sure. They can all cause serious discomfort if consumed.
With symptoms starting within just one to two hours of contact or consumption, one or two berries alone can be enough to trigger signs of Daphne poisoning. Mild cases report irritation in the mouth and throat, abdominal pain, and severe lethargy, with severe cases being marked by vomiting and muscle weakness.
If contact is made with the plant, it is highly recommended to wash the affected area with soap and water, as it is prone to triggering rashes and blisters. If ingested, rinse the mouth thoroughly with water. Luckily for those affected, most Daphne poisonings resolve themselves without treatment in 48 hours.
However, one important aspect of Daphne is that even its aroma is toxic. Pets and humans who inhale the scent of a Daphne may experience nausea or vomiting.
Final Thoughts
The natural world is a delicate balance of beauty and danger. It’s crucial to be aware of the potential hazards that can lurk in our backyards. The 10 most poisonous plants listed above are a testament to the hidden dangers that can be found in nature, and they serve as a reminder that we should exercise caution when dealing with plants, both in the wild and in our gardens.
From deadly nightshade to the sweet smell of oleander, these toxic specimens are a warning that we should educate ourselves about the plants around us. Knowledge is power, and by understanding the dangers poisonous plants pose, we can protect ourselves and avoid potential harm.
So, take a moment to reflect on the power of nature and the importance of being aware of the dangers it can pose.
WARNING – When in doubt, err on the side of caution and consult a professional before handling any potentially hazardous plants. And always seek medical advice in cases of suspected poisoning.
FAQs
What are poisonous plants?
Poisonous plants are plants that contain toxic compounds that can cause harm or death if ingested, inhaled, or maybe if the sap comes into contact with the skin. Many poisonous plants are lethal when consumed above a certain dosage – but even if the lethal amount is not reached, the consumer can still experience severe symptoms.
How many poisonous plants are there in the world?
There is no exact number of poisonous plants in the world, but it is estimated there are over 600 species of toxic plants dispersed across the globe.
What is the deadliest poisonous plant in the world?
The most toxic and deadliest poisonous plant in the world is the belladonna, also known as deadly nightshade. Just 10 bays is enough to kill a full-grown adult.
Can all parts of a poisonous plant be dangerous?
Yes, all parts of a poisonous plant may be dangerous, including the leaves, stems, roots, flowers, and fruit. So, be careful.
What should you do if you suspect someone has been poisoned by a plant?
If you suspect someone has been poisoned by a plant, seek immediate medical attention. In the meantime, try to identify the plant and remove any remaining plant material from the person’s mouth and skin. Keep the person calm and still and provide first aid as needed.
When in doubt, follow the steps below:
- Remove any remaining portion of the plant, berry or mushroom from your or the afflicted person’s mouth
- Save a piece of the plant or mushroom in a dry container for professional identification
- Have the person wash out their mouth thoroughly with water
- Check for any irritation, swelling, or discolouration in or around the mouth
How were the first poisonous plants discovered?
Archaeological findings around the globe prove that, although ancient humans used conventional weapons like axes, and later swords, they also frequently used natural poisons in warfare. Makeshift vials for storing or holding poisons have been found amongst their hunting weapons and tools, showcasing the fact that early humans had discovered poisons of varying potencies and applied them to their weapons collections.
Researchers speculate that the use of natural poisonous substances was kept secret within the more important and higher-ranked members of a tribe. Antidotes were also found, meaning that select members of tribes must have been assigned to test and trial the combinations of specific potentially poisonous plant life.
Do some cultures still use some poisonous plants today?
Yes. In tribal parts of Africa, arrow poisons are typically made using floral ingredients, such as that taken from the plant Acokanthera. These poisoned arrows are also still commonly used in the jungle areas of Assam, Burma, and Malaysia by their native tribes.
The ingredients of these poisons are generally extracted from antiaris and strophanthus plants. The liquid extracted from these plants are smeared on the head of the arrow to inflict their intended target with paralysis, convulsions and/or cardiac arrest. With a high enough dosage, these poisoned weapons can even be deadly.
How common is it to be poisoned by a toxic plant?
Very uncommon. Although poison is the fourth most common reason across North America and the United Kingdom for patients to be admitted to the hospital, plant-related poisonings make up a very small percentage.
Which plants are poisonous to pets?
Plants that are toxic for pets include, but aren’t limited to: marijuana, birds of paradise, lilies, azaleas, English ivy, amaryllis, chrysanthemum, poison hemlock, tulips, mistletoe, nightshade, and oleander.
The ASPCA Poison Control estimates that 25 percent of poisoned pets recover within two hours of ingesting a toxic plant. Even with treatment, only 1 in 100 poisoned pets die. However, immediate medical assistance is recommended.
Disclaimer:
The medical information in this article is provided as an information and entertainment resource only, and is not to be used or relied on for any diagnostic or treatment purposes. This information should not be used as a substitute for professional diagnosis and treatment.
Updates
This article was updated on 2nd March 2023.
