You should NEVER eat unripe elderberries.
An important comment, above. That caution aside, this is good to know if you're ever starving or just have the munchies while wandering through your back yard! :) Read the rest of the article at 52 Plants In The Wild You Can Eat | My Family Survival Plan.
DISCLAIMER: We are not medical professionals but can read what they say in the various articles linked on this site. Think for yourself. Make up your own mind.