Since multiple active ingredients in each herb contribute some type of positive physiological stimulus, this supports the argument that using concentrated extracts of the entire herbal part is much better than just a single ingredient molecule.
This promotes safe use of the herb, too. Many active fractions contribute and there is not an excessive concentration of a single ingredient as is the common case with drug medications. A single active fraction does not address all of the factors contributing to any disorder, while at the same time single fractions are the cause of most, if not all, medication side effects.