Echinacea purpurea

Figure 1. The flowering Echinacea purpurea plant. 

Echinacea purpurea, or sometimes called Echinacea, eastern purple coneflower, purple coneflower, or hedgehog coneflower, is a North American species of flowering plant in the family Asteraceae. Echinacea purpurea is an herbaceous perennial plant that blooms throughout summer into autumn. The leaf, flower, and root of Echinacea purpurea are used as medicine. It has been mainly used in chemo-preventive and chemotherapy for infectious diseases in both upper and lower respiratory systems.

As a dietary supplement, Echinacea purpurea is most commonly used for the common cold and other infections. Echinacea purpurea appears to contain immunostimulatory and anti-inflammatory properties, especially the alleviation of cold symptoms. The plant's other aspects have also been studied for beneficial effects including as antianxiety, antidepression, cytotoxicity, and antimutagenicity. However, there is insufficient scientific evidence presently to conclusively support these applications.

In terms of side effects, findings from clinical trials have been mixed. While some studies reported no severe side effects, others have reported serious side effects such as abdominal pain, angioedema, dyspnea, nausea, pruritus, rash, erythema, and urticaria.