Echinacea (Echinacea angustifolia, Echinacea purpurea) is a native plant of North America whose roots and aerial parts have demonstrated immune-promoting properties since 1913. Echinacea has been traditionally used to promote upper respiratory tract health and support proper wound healing. The active components of echinacea have demonstrated anti-inflammatory and antioxidant properties and may also support healthy microbial environments. 

In vivo investigations suggest that echinacea promotes innate immune activity and supports the immune system’s ability to fight potentially pathogenic microorganisms by activating neutrophils, macrophages, polymorphonuclear leukocytes, and natural killer cells. The roots and aerial parts of echinacea include the compounds believed to be responsible for the immune-supportive and anti-inflammatory properties, such as caffeic acid derivatives like echinacoside.  

A study on ten healthy human subjects demonstrated that daily administration of 100 mg/day of Echinacea angustifolia root extract for a month upregulated mRNA levels of anti-inflammatory interleukin (IL)-2 and IL-8 cytokines while downregulating proinflammatory tumor necrosis factor-α and IL-6 expressions. This suggests the herb’s potential ability to support healthy inflammatory responses. 

Echinacea exhibits high specificity towards enveloped respiratory viruses in vitro and in vivo. This can be demonstrated in human studies, where a randomized controlled trial with 187 children (aged 4 to 12) and a meta-analysis of six clinical trials with 2,458 participants suggest that echinacea supplementation may be clinically beneficial to those with upper respiratory tract infections. 

It is important to note that clinical studies analyzing echinacea's benefits on upper respiratory tract health face certain limitations due to inconsistent echinacea preparations, including differences in the part of the plant used, echinacea species, standardization, extraction methods, and chemical variability of the plant. Hence, standardized echinacea supplementation with labeled plant parts is vital. 

Timing in experimental designs, such as when symptoms appear and when to administer the echinacea supplement, also poses challenges in investigating upper respiratory tract health. A Cochrane review of 24 double-blind trials (n = 4,631) suggested that a number of echinacea products slightly reduce the risk of getting a cold in healthy individuals. However, it was difficult to draw strong conclusions due to significant differences in the preparations tested. 

While more extensive clinical trials are needed, meta-analyses by Schoop et al. (n = 390) and Shah et al. (n = 1,630) indicated that individuals receiving echinacea supplementation had a higher likelihood of avoiding an upper respiratory tract infection and a shorter duration of an upper respiratory tract infection versus a placebo. Specific studies in the meta-analysis combined echinacea with additional immune-supportive nutrients and herbs, such as vitamin C, thyme, and eucalyptus, and also exhibited clinical benefits. Thus, it cannot be determined if echinacea with other compounds yields better results than echinacea alone.

The benefits of echinacea have spread rapidly, resulting in echinacea being the third-highest best-selling herbal supplement in the U.S. in 2015. While more research is needed to fully understand its support for upper respiratory tract health, echinacea holds promise for children and adults to support a balanced and healthy immune system in times of need. 

By Danielle Moyer Male, MS, CNS, LDN