Echinacea

Echinacea encompasses a group of herbaceous plants in the daisy family (Asteraceae) native to North America, where they were traditionally used by Indigenous peoples for wound healing and infections. Modern phytotherapy focuses on three species: E. purpurea, E. angustifolia, and E. pallida. The active constituents include alkamides, chicoric acid, polysaccharides, and glycoproteins, which modulate innate immune responses by enhancing phagocytosis and cytokine production. Meta-analyses suggest that echinacea preparations can reduce the risk of developing a common cold by approximately 10–20 % and shorten symptom duration by about 1–1.5 days when taken at onset. However, considerable variability in species, plant parts, and extraction methods across commercial products makes direct comparisons challenging. Echinacea is generally well tolerated, with rare allergic reactions primarily affecting individuals with Asteraceae sensitivities.