special subjects
Echinacea
Evidence
Studies ofechinacea's role in preventing and/or treating the common cold are inconsistent. The largest factor contributing to inconsistency is the variability of plant preparations (including different plant parts and species) and ultimately composition of the supplement. products to prevent or treat colds. No benefit was shown for prevention, although a post hoc pooling of prevention studies implied a 10 to 20% relative risk reduction. The authors concluded some products had weak benefit ( References ). A 2019 systematic review and meta-analysis of randomized trials assessed the impact of 