Causes

• Some fruits and vegetables have natural poisons. For example, apricot kernels contain enough cyanide to harm or even kill a small child; apple seeds also have cyanide. Other fruits and vegetables are coated in pesticides from the farm, which can cause allergic reactions or illness in people and animals.
  
  

Allergies

• Certain people are born with food allergies that can result in illness or even death when they eat a particular item. Strawberries are a good example of such a plant.
  
  

Considerations

• Sometimes a plant is only dangerous when it is unripe. Green, unripe potatoes can be toxic, so it's important to store them in a dark, cool space to let them ripen. Remove any green parts from an uncooked potato and you should eliminate any chance of reaction.