When was the last time you had a salad made from potato plant leaves and stems? Probably never, since they're just a touch poisonous and not very delicious.
Here are five more everyday foods that contain naturally-occuring toxins:
Part that's poisonous: The double shell which houses the cashew nut, which is why it is almost never sold in its natural state.
Toxin contained: Anacardic acid, which is similar to the toxic compound found in poison ivy, urshiol.
Will it kill you? No. According to the Centers for Disease Control and Prevention, contact with the anacardic acid on the surface of the cashew's double shell, likely during harvesting, may cause an allergic rash on the skin. Store-bought cashews are mostly dried or roasted, with the toxins long gone before the nuts go in your snack.
Part that's poisonous: The pit.
Toxin contained: Cyanogenic glycoside.
Will it kill you? Probably not*. According to the Canadian Food Inspection Agency, eating the flesh of stone fruits like cherries, apricots, plums and peaches is totally safe, but chewing on the pits or kernels will convert the naturally-occurring cyanogenic glycoside into hyrdrogen cyanide. The lethal dose of cyanide ranges from 0.5 to 3.0 mg per kilogram of body weight.
You'd have to eat a lot of chewed or crushed cherry pits to die from cyanide poisoning.
Part that's poisonous: All of it.
Toxin contained: Myristicin.
Will it kill you? Probably not. According to the toxinology journal Toxins, a modest grating of nutmeg in your macaroni and cheese or a pinch in your carrot cake won't do anything to you, but a dosage of at least 6-7 mg/kg body weight may cause psychotropic effects. A low dose of 1-2 mg/kg body weight (about 5 grams) will cause symptoms similar to alcohol intoxication.
Part that's poisonous: The whole plant, although the leaves contain a much higher concentration of poison than the stalk, which is safe to eat.
Toxin contained: Oxalate.
Will it kill you? Probably not, although fatalities from ingesting poisonous rhubarb leaves have been recorded, according to the Canadian Biodiversity Information Facility. Symptoms include abdominal pains, burning sensation in the mouth, convulsions, vomiting and muscle twitching.
Part that's poisonous: The beans themselves.
Toxin contained: Lectins.
Will it kill you? No. But according to Health Canada, consumption of improperly cooked kidney beans has been known to cause abdominal pain, and in extreme cases extreme nausea, vomiting and diarrhea. Canned kidney beans typically don't require further cooking, but dried and soaked beans should be boiled vigorously for 10 minutes before consuming.
*UPDATED 10:29 a.m., September 11, 2015 to remove a claim that consuming 1-2 freshly crushed cherry pits could result in death by cyanide poisoning.