Echinacea for Upper Respiratory Infection

There is currently no universally accepted standardization procedure to ensure comparability among products. Unfortunately, given the apparent multiple chemical nature of Echinacea’s mode of action and the unequal distribution of active constituents in the flowers, leaves, stems, and roots of the 3 medicinal species, it is difficult to determine exactly what kind of standardization would be optimal.⁷¹ As there are a number of substances and mechanisms underlying Echinacea’s observed clinical effects, it seems possible that whole-extract dosing might indeed remain preferable to isolation and purification of single chemical entities. Still, as the concentrations of active ingredients are known to vary by species, among roots, leaves, and flowers, and most likely by season, soil type, and climate, and as there is very little research that tests one formulation against another, no recommendations regarding specific Echinacea products can be made.

Recommendations for clinical practice

The use of Echinacea for the early treatment of the common cold can be cautiously supported. More evidence is needed before clear recommendations can be made regarding specific formulations or dosing. Extracts from E purpurea, E angustifolia, and E pallida roots, leaves, and flowers cannot at this point be distinguished from each other in terms of their apparent beneficial activity. If the decision is made to use an Echinacea product, we recommend that it be taken early in the course of a cold, several times per day, and discontinued as symptoms abate. We recommend that Echinacea not be taken routinely, chronically, or on a preventive basis. We note that no trials have included infants, children, or pregnant women, and recommend caution among those populations. We also note the theoretical contraindication among persons suffering from serious autoimmune disorders.

At the present time we conclude that the evidence suggests Echinacea taken early in the course of an illness may be safe and effective in reducing the severity and duration of the common cold. The evidence of Echinacea’s ability to prevent infection is inadequate to make any recommendations in this regard.