 Because otherwise, all parts of the plants are poisonous, especially the berries. Somebody was asking if the berries can be eaten. And they look like they could, right? Because they're that dark purple. And it's usually white berries that you associate with. So cooking it is like boiling something to get rid of the poisons? Personally, I wouldn't take a chance. That's such a terrible term for a food if you need to cook it.