Many everyday foods contain natural compounds that can be harmful if they’re not prepared the right way. These chemicals are part of the plant’s natural defense system and are usually harmless once the food is handled correctly. In many cultures, safe preparation techniques have been passed down for generations. Cassava is one example—widely enjoyed around the world but only safe after soaking, fermenting, or thoroughly cooking to neutralize the compounds that can release cyanide in its raw form.

Starfruit is another food that deserves attention, especially for people with kidney conditions. While perfectly safe for most individuals, it contains substances that healthy kidneys filter easily but may pose issues for those with reduced kidney function. Meanwhile, certain fruit pits and seeds—such as those from cherries, apples, and bitter almonds—contain small amounts of amygdalin. Accidentally swallowing a single seed isn’t harmful, but consuming them in large quantities or crushing them intentionally can be unsafe.

Potatoes also have their own natural defense mechanism. When they turn green or begin to sprout, they can develop higher levels of solanine, a substance that may cause digestive discomfort. If a potato tastes bitter or has distinct green patches, it’s best to discard it. Raw kidney beans fall into a similar category; they must be boiled properly to break down lectins, which are present in higher concentrations before cooking.

Other foods require simple but essential caution. Rhubarb leaves should never be eaten, and elderberries should be cooked fully to avoid stomach upset. At the more extreme end of the spectrum is pufferfish, a delicacy prepared only by certified experts due to its potentially dangerous toxins. These examples highlight an important truth: understanding how certain foods should be handled ensures safety while allowing us to enjoy diverse ingredients from around the globe.