Dietary
The fruits are edible, preferably cooked, raw they can upset the digestive system.
Flowers, dried and ground (flour).
Leaves, wood and roots contain purgative substances, avoid.
Other
It is easy to scoop out a branch of Elderberry as spinal center comes apart easily, the wood has already served to make flutes, tubes for maple syrup, blowguns, etc... Again beware of the purgative substances.