Before we read on elderberry benefits, it is important to note that the berries should be harvested only when they are ripe. The raw berries are known to be a little poisonous. At the same time, it is important to stay away from the stem of this plant, as it contains cyanide which is very harmful. Coming back to the benefits, the syrup or juice of this elderberry is known for its medicinal properties. It has been used to treat common cold, influenza, etc., in Europe for a very long period of time.