The hard stone in the center of cherries is full of prussic acid, also known as cyanide, which is poisonous. But there's no need to freak out if you accidentally swallow one -- intact pits just pass through your system and out the other end. Avoid crunching or crushing pits as you nosh on your cherries.
Apple seeds also have cyanide, so throwing back a handful as a snack isn't smart. Luckily, apple seeds have a protective coating that keeps the cyanide from entering your system if you accidentally eat them. But it's good to be cautious. Even in small doses, cyanide can cause rapid breathing, seizures, and possibly death.
You may take elderberry as a syrup or supplement to boost your immune system and treat cold or flu symptoms or constipation. But eating unripe berries, bark, or leaves of elderberry may leave you feeling worse instead of better. They have both lectin and cyanide, two chemicals that can cause nausea, vomiting, and diarrhea.
Nutmeg adds a nice, nutty flavor when you add it in small amounts to baked goods. But eaten by the spoonful, it can cause big problems to your system. Even as little as 2 teaspoons can be toxic to your body because of myristicin, an oil that can cause hallucinations, drowsiness, dizziness, confusion, and seizures.
The leaves, sprouts, and underground stems (tubers) of potatoes contain a toxic substance called glycoalkaloid. Glycoalkaloids make a potato look green when it's exposed to light, gets damaged, or ages. Eating potatoes with a high glycoalkaloid content can cause nausea, diarrhea, confusion, headaches, and death.
Raw Kidney Beans
Of all the bean varieties, raw red kidney beans have the highest concentration of lectins. Lectins are a toxin that can give you a bad stomachache, make you vomit, or give you diarrhea. It only takes 4-5 raw kidney beans to cause these side effects, which is why it's best to boil your beans before eating.
Eating the stalk is OK, but leave out the leaf. Rhubarb leaves contain oxalic acid, which binds to calcium and makes it harder for your body to absorb it. In turn, your bones can't grow the way they should, and you're at risk for kidney stones, blood clotting problems, vomiting, diarrhea, and coma.
Both types of almonds -- bitter and sweet -- have amygdalin, a chemical compound that can turn into cyanide, but bitter almonds have the highest levels by far. Sweet almonds are safe to snack on, but eating untreated bitter almonds can cause cramps, nausea, and diarrhea.
If you have kidney disease, it's best to leave star fruit out of your diet. Normal kidneys can filter out the toxins in this sweet fruit, but for a system that can't, the toxin sticks around and can cause mental confusion, seizures, and death.
They may be great on pizza, but beware of certain mushrooms in the wild. Two types are particularly harmful -- the death cap (Amanita phalloides), and the destroying angel (Amanita virosa). Eating these wild mushrooms can cause abdominal pain, diarrhea and vomiting, dehydration, intense thirst, liver failure, coma, and death.
The cashews you get in stores with a raw label aren't exactly that. Before they hit shelves, they're steamed to remove a toxin called urushiol in their shells. Urushiol is the same toxin you find in poison ivy. Eating pre-steamed cashews can cause an allergic reaction and can be fatal if your allergies are severe.
Just like raw cashews, the skin, bark, and leaves of mangoes contain urushiol, the toxin in poison ivy. If you're allergic to poison ivy, especially if that allergy is a bad one, biting into a mango can cause a severe reaction with swelling, rash, and even problems breathing.