Don't Eat Apple Seeds
Approximately 2% of the population lacks enzymes that break down apple seeds in the digestion process. Sometimes these people eat apple seeds and the seed gets stuck in the lining of their intestine -- many of these people actually have trees growing inside them and don't know it. The trees don't get very big because they don't get enough light. This happened to my grandmother and they only found out about it when they were operating on her stomach. The surgeons couldn't remove the tree because its root system was tangled up with her intestines, so they called in an emergency arborist to prune it.