Elderberry is a veritable medicine chest, enriched over the centuries by empirical and then scientific research that has never run out of steam. The first monograph on elderberry, published in 1631, contains at least 450 treatment formulations based on one part of the shrub or a combination of several! An entire chapter of My friend the eldertree is devoted to the development of preparations that can be used for gentle self-medication. Some of these have been modified in the light of recent scientific publications. For example, adding a small amount of citric acid to flower- or berry-based preparations improves the quantity, quality and preservation of the most precious substances extracted from the plant.