The berries of elderberry are not actually berries, they are drupes.

Taste. Elderberry has a tart flavor, which may well migrate into the bitter. Sour components are also given. Often the berries have an additional sweet aftertaste.

Effect. The berries, which are actually drupes, contain vitamins A, B and C, potassium, fruit acids, essential oils and antioxidants. The latter are known to protect cell membranes from free radicals. These radical scavengers not only slow down the aging process of cells, but also reduce the risk of cancer and cardiovascular diseases.

Source: www.botanikguide.de