6 Secretly Poisonous Plants We Eat All the Time - Modern Farmer

6 Secretly Poisonous Plants We Eat All the Time

Beware of these plants - or parts of these plants - which you probably eat and enjoy often!

Jo Jakeman, Flickr

The tomato, of course, is not poisonous, but the Europeans were right to be wary of it. There are plenty of fruits, vegetables, tubers, and other plants that we heartily consume that are, secretly, dangerous to our health if prepared or eaten improperly. Here are some you may not have known about.

1. Tomato

I know, I just said the tomato isn’t poisonous. The fruit isn’t, but the leaves, roots, and stem (and, in limited doses, even some unripe fruit) are rich in tomatine, an alkaloid that’s mildly toxic to humans. It won’t kill you, unless you chow down pounds and pounds of it, but it is likely to cause you some gastrointestinal distress.

Flickr user Swong95765

Flickr user Swong95765

2. Apples, Cherries, and Apricots

The seeds of all of these fruits are not considered edible; they’re hard, bitter, and unpleasant. That bitter flavor is a protective element: The plant puts it there to discourage animals like us from destroying them. And it comes from a substance called amygdalin, which turns into cyanide when it comes into contact with acids in the human digestive system. Cherries, apricots, peaches, and nectarines have the substance in much higher concentrations than apples, but all of the seeds and pits in these fruits are fantastically tough. Even if you swallowed some? No big deal. Your body will simply pass them out. That said, please do not pulverize and then consume cherry pits.

3. Kidney Beans

Many legumes can cause mild gastrointestinal distress when undercooked, but red kidney beans (the kind almost always used in chili) are special. Kidney beans contain phytohaemagglutinin, a chemical compound that I will always have to copy and paste because, are you kidding me with that word? Ingestion of even just a few undercooked kidney beans can cause serious diarrhea and vomiting. According to the FDA, it’s not fatal and rarely results in hospitalization, but it’s fairly common for people to end up sick after chomping down on some merely soaked beans.

Flickr user dominik18s

Flickr user dominik18s

4. Rhubarb

Rhubarb, a springtime stalk most commonly used in the creation of America’s best pie, the strawberry-rhubarb, is a very strange plant indeed. Most often used in sweet applications, it’s a sour vegetable that looks like crimson celery. And its leaves are spectacularly poisonous. Rhubarb leaves are very high in oxalic acid, which quickly causes kidney failure in humans. About 25 grams of pure oxalic acid is the average amount needed to kill a human. That said, rhubarb leaves aren’t pure oxalic acid, and it would take around 11 pounds of the leaves to secure that much. But still! I’d stay away.

Flickr user Emma Forsberg

Flickr user Emma Forsberg

5. Asparagus

Like the rhubarb, the part of the asparagus plant that we love – the young stems – are perfectly safe to eat. But the asparagus hides a deceptive, nasty secret: Its fruit, which are bright red berries, are toxic to humans. Just a handful can cause vomiting and diarrhea, though a bit of charcoal will clear that right up, according to the excellently named Asparagus Friends site.

Flickr user Harry Rose

Flickr user Harry Rose

6. Cashews

Cashews are another delicious product that should never, ever be eaten raw. (When you buy them, they’ve usually been roasted.) Native to the Amazon, the cashew is not really a nut, but rather a seed that protrudes oddly from the bottom of a fruit (also edible, though rarely seen outside the tropics) called the cashew fruit. You may have noticed that cashews are never found in their shell as almonds or peanuts are, and that’s because when raw, they’re covered with anacardic acid, closely related to the acid that makes poison ivy so irritating. It’s much worse when you eat it.

Flickr user Abhishek Jacob

Flickr user Abhishek Jacob


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phytohaemagglutinin — take it apart and put it back together… makes it a lot easier:
phyto = plant
hemo/haemo = blood
agglutin = glued together
in = a chemical substance
phyto + hemo + agglutin + in = a chemical substance from plants which makes blood cells clump together — not something you’d want to have happening within your circulatory system


Great, now I have to delete this article before my wife see’s it. 🙁

Julie K Whitmore

And yet, and yet, deer invading my garden will chow down on rhubarb, tomato and potato leaves with no ill effects. Sigh.

R White

Tomatoes are dangerous in that they along with peppers, aubergine/eggplant and potatoes are all part of the NIGHTSHADE family and eating them may give your athritis pain sin your legs, hips and back!
If you are getting these painsa nd locked joints try cutting out all these fruits and potato for a week to see if your symptoms magically clear up!

JoeAnn Cotton

Thanks for the information


It is a little misleading to say “Cashews … should never, ever be eaten raw.” Store-bought raw cashews, which have their shells removed and are common to every health food store and most grocery stores are perfectly safe to eat. One just should not attempt to eat them raw directly from the tree, as the de-shelling process to make the seed safe is the dangerous and labor-intensive part.

Nice guide. I so much appreciated


Thanks for your article.
It was just as educational as it was entertaining!

Cindy donahey

I just read a recipe for heating I think apricot pits and adding the result to vodka to make some kind of almond extract. Heating is supposed to destroy any poison. Have not acted. Upon this.


Great info, thanks

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