These Plants Could Kill You

When you look at a plant your first thought is probably not "that thing's going to kill me". But in some cases, that thing is going to kill you. Plants have evolved with all kinds of compounds inside them. Sometimes those compounds don't play well with human biology.

Dumbcane - Dieffenbachia

A common houseplant, it's easy to grow and nice to look at, but if you eat any of this stuff, you'll end up with blisters and swelling in your mouth and throat that can make it difficult to breathe or speak, hence the name.

The main problem comes from tiny crystals of calcium oxalate and acid that's a major component of kidney stones. The crystals are shaped like needles and they'll easily stabbed through the tissues in your digestive system or eyes like some kind of poisonous acupuncture.

Botanists think the needles might also contain enzymes that mess with the proteins in your cells, which help make the swelling and burning worse. The effects can last for up to two weeks and can be fatal if the airway gets blocked. Though deaths from dumb gain are relatively rare.


Foxglove - Digitalis

This plant contains digitoxin, which is toxic to humans. Although it can be used as a heart medication in smaller doses. Eating Foxglove generally leads to symptoms like nausea, vomiting and diarrhea as well as confusion hallucinations and an irregular heartbeat. It can also affect your vision making things look blurry and yellowish.

It's thought that Van Gogh might have been experiencing this during what art historians call his yellow period. It's possible that he was given medicine containing digitoxin to help treat his seizures.

Like with Dumbcane, fatal cases of Foxglove poisoning are rare because most people don't go around munching on buckets this stuff.


Pong Pong - Cerbera odollam

This is a tree native to Southeast Asia and some Pacific Islands, about 10 meters tall and, from the outside, it looks pretty normal but even one seed would be enough to kill you. The trees seeds contain cerberin which is similar to digitoxin in the sense that it interferes with normal heart function. It's thankfully not easy to ingest the seeds by accident they have to be removed from a harder husk first. But people who do end up with Cerberin poisoning experience stomach symptoms and changes to their heart rhythm and often die within a few hours.


Oleander - Nerium oleander

Pliny the Elder wrote about it way back in the year 77 CE, describing the shrub as deadly to livestock but a cure for snake bites. To be clear, if you ever get bitten by a snake and find some oleander nearby do not eat the oleander. It doesn't actually work as an antidote to snake venom and eating it would probably just speed up the whole dying thing. It contains different poisonous compounds but the main one is the appropriately named oleandrin which, once again, interferes with the hearts beating and can eventually be fatal. Other symptoms include nausea, vomiting, diarrhea plus dizziness, disoriented, and blurred vision.


Aconite - Aconitum carmichaelli

I'd like to direct your attention to the book Harry Potter and the Philosopher's Stone. In Harry's very first potions lesson, Snape asks him about the difference between Monkshood and Wolfsbane. We later find out that they're actually the same plant also called Aconite. What the books don't mention is that this plant is also incredibly poisonous because of a compound known as aconitine. People who eat aconite, especially the roots or tubers, can end up with muscle weakness, tingling, numbness, irregular heartbeat, low blood pressure, nausea, vomiting and diarrhea. These days about 6% of people who are hospitalized with aconite poisoning die.


Hemlock - Cicuta, commonly known as water hemlock.

Another poisonous plant that's been made famous by ancient writings, including accounts of Socrates's execution. People have also been poisoned by accident since hemlock can look a lot like wild parsnips, celery, and carrot plant. Hemlock contains coniine, which interferes with the signals between neurons and the effects are not pretty. The poison causes dizziness and trembling, slows down the heart rate and eventually can cause paralysis. It can be fatal, because the diaphragm the muscle that helps control breathing also becomes paralyzed. But, generally, if a modern patient can get on a ventilator to help them breathe until the poison wears off, they'll be okay.


Deadly Nightshade - Atropa belladonna

To the untrained eye it's berries might look like blueberries. Eating deadly nightshade is not a good idea, 10 to 20 berries can be enough to kill an adult. The plant contains compounds called atropine and solanine. Atropine is also used as a medication but not in such high doses, and not in combination with a second deadly poison. These two chemicals attack the human body in all kinds of ways, which is why deadly nightshade is another poison that causes practically every symptom possible.

Apparently, it is possible to build up a tolerance to it. History is full of stories of assassins who use their own tolerance to trick their victims into drinking poison.


Rosary Pea - Abrus precatorius

Just a bright red berry on a bush but it contains one of the most poisonous substances in the world, and there's no antidote. The compound is called abrin, and it's different from all the other poisons we've talked about so far because it's a protein.

Abrin is what's known as a Ribosome-inactivating Protein. That means when it gets into a cell, it stops that cells ribosomes from functioning. The problem is cells need ribosomes because they make proteins. When they can't make new proteins, cells stop working.

This stuff is so potent that just one 10th of a milligram can kill an adult. The symptoms usually set in within the first day, and start with gastrointestinal problems. Eventually though the victim gets to look forward to internal bleeding and organ damage and then, in almost all cases, death.


White Snakeroot - Ageratina altissima

This plant contains a mix of compounds known as tremetol, which gets its name from the trembling it causes. You probably need to eat 5% to 2% of your body weight to die.

In the 19th century, it caused a huge problem in the American Midwest. People were dying and nobody really knew why. It was because their livestock were eating tons. Tremetol would end up in the animals milk and then people would die from drinking it. They called it milk sickness. This is actually how Abraham Lincoln's mother, Nancy Lincoln, died in 1818.

Eventually, a doctor named Anna Bixby identified the white snakeroot as the cause, with the help of a local Shawnee woman. People started removing it from the places where the animals graze.


Manchineel Tree - Hippomane mancinella

The last one is sometimes called the "little apple of death", or just the "world's most dangerous tree". That's probably an exaggeration, but it does cause unbelievable amounts of pain. Not only should you avoid eating it, you shouldn't touch it either, or even go near the thing. It's only found sparingly around Central and South America. Manchineel contain all kinds of toxins and we don't even know what they all are yet. The tree and especially its sap will make human skin burn and blister even if all you're doing is standing under it in the rain. Just the smoke from burning its wood is enough to blind you. If you trie to actually eat the fruit you'd experience burning irritation and swelling in your mouth throat and the rest of your digestive tract. Deaths from eating manchineel fruits are rare, probably because most people don't keep eating after the first bite. It's also hard to get ahold of in the first place because the tree is endangered.