[♪ INTRO] People love plants, for food, decoration,
or just because taking care of a succulent is a lot less responsibility than a puppy. But many of the house plants that spruce up
our surroundings are also poisonous. Kids and pets are the usual victims in plant
poisonings because they have a tendency to explore the world with their mouths. In fact, when the American Association of
Poison Control Centers compiles their annual poisoning report, plants are typically in the top 10 causes
of accidental poisoning in children. So you can be aware of the dangers lurking
in your house, here are 9 plants you might have around your home that are actually pretty
toxic if they end up inside you. Dieffenbachia is a popular house
and office plant because it can survive without much sunlight or TLC. But it can be bad news if you mess with it. This plant has specialized cells that contain
calcium oxalate crystals. That’s the same chemical that makes up most
kidney stones, which get stuck in the tube that connects your kidneys to your bladder. Erh. In Dieffenbachia, these crystals can come
in a couple different shapes. Druses have a star-like shape, while raphides
are needle-like. And researchers think that calcium oxalate
crystals might have different functions in different parts of the plant, from deterring
hungry herbivores to adding structural support. For instance, if cells in the tasty-looking
leaves are damaged, like by chewing, they can forcefully expel the raphides
like microscopic darts. These stabby crystals, and
other plant proteins on them, can severely irritate the
delicate tissue in a mouth. In humans, the swelling they cause can make
it difficult to talk, hence Dieffenbachia’s common name: dumb cane, dumb being an antiquated,
insulting term for someone who can’t speak. And if you’re unlucky enough to get a squirt
of sap in your eye, those crystals can damage your cornea, the clear protective covering
on the front of your eyeball. Like any other scratch, this can typically
heal. But it’s definitely not pleasant. Now we usually grow daffodils and other members
of the genus Narcissus from bulbs, they’re a classic, cheery spring flower! But they also contain a toxin called lycorine,
which is a type of alkaloid. Alkaloids are nitrogen-containing chemical
compounds made by lots of living things, including many plants. They can be another way of deterring herbivores. We humans use some alkaloids on purpose, like
caffeine or nicotine, even though they can have really extreme effects on our bodies. And lycorine is no exception, it causes vomiting, diarrhea, trembling,
convulsions, and sometimes even paralysis. Exactly what it does in our cells isn’t
well understood. Although there’s some evidence it might
mess with protein synthesis. People usually don’t eat daffodils on purpose, but they can accidentally eat the
bulbs thinking that they’re onions. And that’s what happened to some school
kids in Suffolk, England in 2009. The kids were making soup using vegetables
from a garden they had planted, when someone accidentally added a daffodil bulb to the
pot. And a bunch of the kids got sick. Thankfully they were all fine afterwards, and hopefully they weren’t too
put off from eating their veggies! Oleander is a popular landscaping shrub in
the warmer parts of the US because it’s low maintenance, drought tolerant, and has
some lovely flowers. But there are some not-so-lovely parts too,
like cardiac glycosides. Cardiac glycosides are toxins produced by
many different species of plants to, you guessed it, deter herbivores. Oleander specifically has chemicals called
oleanderin and neriine. And they interfere with the sodium-potassium
pump in heart muscle cells. The sodium-potassium pump does exactly what
you’d think from its name: it pumps sodium and potassium ions back and forth across the
cell membrane. This helps build up electric charges, and
generates a cardiac action potential, which helps coordinate signals that regulate heart
muscle contractions. So if you mess with the sodium-potassium pump,
you mess with your heartbeat. Specifically, cardiac glycosides inhibit the
sodium-potassium pump and reduce the amount of sodium ions it can pump out of the cell. This slows down the heart rate, but increases
the force of the heart muscle contractions. Now, other cells in your body
have sodium-potassium pumps too, including nerve cells and
the cells lining your gut. So Oleander can mess with these too, leading
to convulsions and gastrointestinal symptoms like nausea, abdominal pain, and vomiting. None of which sounds particularly fun. Now, Rhododendrons are popular landscaping
shrubs in the wetter parts of North America, but this widespread genus of plants is also
native to Asia. And in the 1st Century BCE,
they may have contributed to the defeat of the Roman army in Turkey. See, the pollen and nectar in rhododendron
flowers contain grayanotoxins. Like cardiac glycosides, grayanotoxins also
interfere with cells’ ability to move ions across the cell membrane. But they mostly affect nerve cells, so they’re
considered a neurotoxin. They bind to sodium ion channels in the cell
membrane, little pores that open and shut to let sodium ions move into and out of the
cell, which helps generate action potentials. And when a grayanotoxin binds, sodium channels
get stuck open, which causes all kinds of mayhem in your brain, heart, and gastrointestinal
tract, from hallucinations to vomiting. Now, even though humans might not munch on
rhododendron flowers for fun, bees visit these flowers and make honey, which we have been
known to eat. This toxic honey is called Mad Honey, also
the name of my elementary school rock band. So the story goes: when the Roman army invaded
what is now Turkey, the locals lined the route with chunks of this Mad Honey honeycomb. The Romans couldn’t resist the sweet treat,
so they suffered from the toxic effects, and the sick and delirious soldiers were easy
to fight off. So I guess the moral of the story is: Never
eat mystery road honey! A favorite flower for bridal bouquets and
shady spots in the garden, Lily of the Valley has a shady side too. Which you might know if you’re a fan of
Breaking Bad. Lily of the Valley contains nearly 20 or more
different cardiac glycosides, the same kind of toxins found in Oleander. One of the major ones is convallotoxin, which
is one of the most active natural substances affecting the heart that we know of. Like all cardiac glycosides, it messes with
the sodium-potassium pump and wreaks havoc on your heartbeat, so it gets slow and irregular,
or in extreme cases, undergoes cardiac arrest. Lily of the valley also contains other toxins
called saponins. These aren’t very toxic by comparison, but
if you eat a lot of them, they’ll give you a pretty upset stomach. Saponins are a lot like soap. They’re surfactants, which means their molecules
have a hydrophilic, or water-friendly, end and a hydrophobic, or water-avoiding, end. And you know what else is made up of carefully
arranged hydrophilic and hydrophobic parts: Your cell membranes. So because they’re surfactants, saponins
can punch holes in cell membranes. And the cells lining your gastrointestinal
tract do not appreciate this. Most of the time when someone is poisoned
by Lily of the Valley, it’s an accident. Like a little kid that tried eating the plant’s
inviting red berries, or one case study in a medical journal of an elderly woman with
dementia who loved the scent of some she was given as a gift, and unfortunately ate them. Hydrangeas’ fluffy flower poofs may look
pretty innocent, but they pack a surprise, a toxin called hydrangin. Hydrangin is a cyanogenetic glycoside and
when you eat it, some enzymes in your body convert it to hydrogen cyanide, which you
may have heard of before. It’s real toxic stuff. Cyanide binds to certain iron-containing molecules
in your cells, and shuts down the cells’ ability to make that all-important fuel molecule:
ATP. Without ATP, your cells quickly starve and
die, and so will you. Thankfully your body can detoxify moderate
amounts of cyanide, so you'd have to eat a lot of hydrangeas to kill you. And they taste pretty nasty, so a large helping
would be hard to swallow. But even eating small amounts of hydrangea
will make your digestive tract cells unhappy and cause diarrhea, vomiting, and stomach
ache. So if your kid or pet eats them, you should
still get them checked out. Sago palms are another landscaping plant used
in the warmer parts of North America. But they’re not closely related to tropical
palm trees at all, they’re actually part of an ancient group of plants called cycads. Cycads were particularly abundant during the
Jurassic Period, so you might remember them from your dinosaur picture books. But even if they look cool, they’re hiding
a dangerous chemical called cycasin. It’s not really the cycasin itself that’s
the problem. But when your body breaks it down,
one molecule that gets produced is methylazoxymethanol or MAM. Now, MAM has a habit of damaging DNA, particularly
in developing brain cells and liver cells. Which sounds pretty bad. It’s a DNA alkylating agent, which means
it binds to DNA and can break strands or make them stick to each other. Which makes it hard for DNA to function or
replicate properly, and that can kill affected cells or cause them to become cancerous. Still, you’d probably have to eat a lot
of cycad to get enough MAM to cause problems. But on certain islands in the South Pacific
where people eat flour made from cycad seeds, there are higher-than-normal rates of neurological
diseases like Parkinson’s and ALS. And some scientists think that cycads might
be partially to blame. One festive winter holiday tradition is decking
the halls with boughs of holly, and with other poisonous plants too. But I’m not talking about poinsettias, they’re
only mildly toxic. You’d have to eat about 500 leaves to get sick, and they taste terrible so it wouldn’t be easy. Mistletoe, on the other hand, can be much
worse. Now, mistletoe species that are native to
North America aren’t very toxic. But mistletoes in the genus Viscum from Europe
have a toxin called viscumin, which is similar to ricin, which you may have heard of before. Ricin is a strong poison made from the castor
oil plant and was allegedly used in a tiny pellet during the infamous umbrella assassination of the Bulgarian dissident Georgi Markov
during the Cold War. And viscumin seems to be just as deadly. An injected dose as small as 2.4 milligrams
per kilogram of body weight can apparently kill a mammal. Both ricin and viscumin are ribosome-inactivating
proteins, also known as RIPs, which is a kind of morbidly appropriate initialism. Ribosomes are the structures in your cells
that assemble proteins, which do all kinds of work to provide structure and regulate
functions throughout your body. When viscumin enters the cell it breaks up
an important part of the ribosome, causing irreversible damage and shutting it down. And if your cells can’t make proteins, you’re
in trouble. Because everything starts breaking. So, uh, even if there’s some smooching,
don’t nibble on the mistletoe by mistake. Potted cyclamen are popular gifts during the
holidays, too. They have delicate, colorful flowers, tend
to bloom in the winter months, and can be grown outside in mild climates. But they also contain the toxin cyclamine,
which is a type of triterpenoid saponin. Like the saponins in Lily of the Valley, this
toxin can mess with your cell membranes and irritate your gastrointestinal tract, making
you feel pretty lousy. Thankfully, most of the cyclamine is tucked
beneath the soil in the plant’s rhizome, which is kind of like an underground stem. And all that cyclamine gives the the rhizome
a very bitter taste too, so even curious kids or dogs are unlikely to eat enough of it to
get seriously ill. The leaves contain less cyclamine, and in
traditional Greek cuisine some species were used to make dolmas, little leaf wraps stuffed
with rice and other fillings. But, like, please don’t pretend
you’re on Iron Chef and make dolmas at home
using random houseplants. It’s not a good party idea. In fact, “don’t eat the houseplants”
is generally a good rule to live by! You can rest easy for the most part, because
it’d probably take a lot to get seriously harmed by these plants, even with their toxic
defenses. But it’s always a good idea
to contact Poison Control and seek medical attention
if it happens, just in case. Thanks for learning with us here on SciShow! If you’re still curious about poisons, and
who isn’t, check out our list show about 6 so-called undetectable ones and how scientists
can actually sleuth them out. [♪ OUTRO]
