I've seen claims both ways on leaves - poisonous and not - I've only eaten them cooked and don't particularly like them.  The young stalks are the only part universally agreed not to be poison, that is the part I have eaten often (older stems gain poison later - rule of thumb is not to eat them after they start turning purple, though I have eaten them up until they started getting woody without problems).  Some sources claim the berries are poisonous some claim not, but I grew up being told they were poison and have never tried them.  And the root is universally agreed to be seriously poison.