echinacea

Echinacea is a genus of herbaceous flowering plants in the family Asteraceae, native to central and eastern North America. The most commonly used species are Echinacea purpurea, E. angustifolia, and E. pallida. They are also grown as ornamental perennials, known for coneflower heads with purple to magenta rays.

Traditionally used by Indigenous peoples for wounds, infections, and fever, echinacea entered Western herbal medicine in the 18th–19th centuries. In modern herbalism, preparations may be made from roots, aerial parts, or whole plants and sold as tinctures, extracts, dried powders, tablets, and capsules. Active constituents include alkamides, polysaccharides, and phenolic compounds such as caffeic acid derivatives (notably cichoric acid) and echinacoside, which may contribute to immune-modulating effects.

Clinical evidence on echinacea for preventing or treating the common cold is inconclusive. Some randomized trials report modest reductions in duration or severity, but many show no significant benefit. Systematic reviews note heterogeneity in products, dosages, and study quality, leading to uncertain overall effects. It is not a substitute for standard medical care or vaccines.

Safety considerations: echinacea is generally well tolerated, but can cause allergic reactions, especially in people with hay fever or allergies to daisies, asters, or ragweed. Gastrointestinal upset and skin rashes have been reported. Rare hepatotoxicity cases have been described but lack clear causal evidence. Caution is advised in autoimmune diseases or when taking immunosuppressants; safety in pregnancy and breastfeeding is unclear.

Taxonomy and cultivation: The genus includes several species beyond the three most used, with E. purpurea the most cultivated for medicinal and ornamental use. Echinacea plants are perennials; they prefer sunny locations and well-drained soil, propagated by seed or division. They are widely cultivated in North America and Europe.