I bought a container of elderberries at the farmer's market. I asked the seller what she used them for. She said she froze them and put them in her tea in the winter. She also indicated that her children ate them raw off the vine.
Here is how they grow. I removed all the berries from the stems and popped a few in my mouth. Warning: I later read that raw berries may be poisonous! Also the leaves and stems. So don't try that yourselves.
That said, the berries are rich in vitamin C and antioxidants. Elderberry tea and juice are used to fight colds and the flu. Elderberry tea is made from the flowers. Flowers and fruit are used to make wine, jam, pies and syrups. If you buy this medicinal remedy it is best to buy it from an authorized maker of such things.
If I were still making paper, I might use these berries to color the paper. I did that with blueberries once. You can see how stained the bowl and my hands are with a lovely purple. These berries sure are purty.