Echinacea is the purple-flowered herb commonly taken in hopes of preventing or shortening the common cold.
The name refers to a group of North American flowering plants in the daisy family, especially Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida. Their flower heads have prominent spiny central cones, which inspired the genus name: echinos is Greek for “hedgehog.”
Echinacea became popular in modern cold remedies during the 20th century, although Indigenous peoples used several species traditionally for ailments including sore throats, toothaches, and wounds. Supplements may contain different species, plant parts, extracts, and combinations, so products sold under the same name are not medically identical.
A common mix-up is treating “commonly taken” as proof that it works. Research remains mixed: some studies suggest certain preparations may modestly reduce cold risk or duration, while others find no meaningful benefit. Echinacea can also cause allergic reactions and interact with medicines.