Toxicity is always variable depending on a number of factors including dosage, exposure, gender, body size and how the substance is metabolized by an individual. Even drinking too much water or eating too much salt can be harmful or even fatal in large doses.

Given a high enough dose, pretty much anything can be toxic.

Many common foods contain naturally occurring toxins that, if eaten in large enough quantities, can even prove fatal. Some foods we avoid because we know they can be dangerous.

For example, some mushroom varieties have a high toxin level. Other foods might surprise us with their hidden toxins.

Apple seeds and pits from cherries, peaches, apricots and pears contain a type of hydrogen cyanide called prussic acid, which can be deadly. Don’t panic if you accidentally swallow some apple seeds, but don’t chew them or ingest any ground up seeds or pits. It would take about a cup of ground pits to be fatal.

Rhubarb leaves contain oxalic acid, which can cause serious kidney stones. It’ll take 11 pounds of leaves to be fatal, but smaller amounts could make you seriously ill.

Nutmeg is a hallucinogenic. Grating a bit over your food won’t cause harm, but consuming it in large quantities could cause myristicin poisoning, which causes headaches, nausea, dizziness, hallucinations, seizures, convulsions and even death. Eating just 0.2 to 0.3 ounces of nutmeg can cause problems.

Potato leaves, stems and sprouts contain glycoalkaloids, which can cause cramping, diarrhea, confusion, headaches, and even coma and death. Glycoalkaloids can build up in the potato itself, if it’s left too long, especially in the light. For this reason, you should avoid potatoes with a greenish tinge. Just three to six milligrams per kilogram of body weight can be fatal.

There are two kinds of almonds, sweet almonds that we find in stores and bitter almonds that are usually wild. The bitter ones contain a relatively large amount of hydrogen cyanide. Eating just a small handful of these can cause problems for adults and could be fatal for children.

Tomato leaves and stems contain alkali poisons that can cause stomach upset. Unripe green tomatoes can have the same effect. You would need to consume vast quantities for it to be fatal, but smaller amounts could cause stomach distress.

Raw red kidney beans contain the toxin phytohaemagglutinin and must be boiled for 10 minutes before they are safe to eat (canned beans have been through this step). Don’t cook these beans in a slow cooker or below boiling as this can multiply the toxicity of the beans. Symptoms include severe nausea and vomiting.

If you happen to have a peanut allergy, then all things peanut can prove fatal. This fairly common food allergy can cause anaphylaxis or severe constricting of the airway, which can result in death if treatment is not prompt.

Honey is a natural food that can be dangerous. Because raw honey is not pasteurized, harmful toxins may be present. A common one is grayanotoxin. Just a tablespoon of honey contaminated with grayanotoxin can lead to dizziness, weakness, excessive sweating, nausea and vomiting that lasts for 24 hours. Honey can also carry botulism spores. This is why you should not give honey of any kind to children less than a year old.

Toxicity is always variable depending on a number of factors including dosage, exposure, gender, body size and how the substance is metabolized by an individual. Even drinking too much water or eating too much salt can be harmful or even fatal in large doses.