Constituents and tissue affinities in herbal medicine.

Western-trained researchers and clinicians can better understand herbal medicine if they master at least a basic set of essential concepts used by herbal practitioners to describe how herbs work. Constituents, such as carotenoids and flavonoids, can all be used to develop a basis for imputed herb actions. Tissue affinity is also an important concept shared by all herb traditions, which can enhance clinical results and illuminate traditional herbal use.