ABSTRACT
A comparatively ancient folk remedy, echinacea preparations are among the most widely used herbal preparations. Nevertheless the evidentiary basis for the use of these materials as immunostimulants and for wound healing is inconsistent. Although many studies have been performed, the results are divided between those supporting significant activity and those that suggest inactivity. No completely convincing evidence is yet in hand identifying any active constituent. The problem is compounded by a collection of factors decreasing confidence in the literature available: poor species identification, adulteration, uncertain quality control, failure to indicate how the preparations have been processed and stored, unclear end points, and poorly controlled clinical trials characterize many of the studies.
