Echinacea angustifolia is a flowering plant species endemic to North America. This plant was recognized as a  medicinal herb by Native Americans and became popular during the 18th and 19th centuries, as it was introduced to Westerners. Its extract is often used to prevent and treat upper respiratory tract infections, such as colds and flu, and as an immune stimulant. Its roots and aerial parts may be consumed raw or in formulations. Echinacea tea can boost the immune system, alleviate pain, function as a laxative, and relieve upper respiratory issues. It is also applied topically to rinse mouths and to help skin problems like acne, inflammation, boils, and wounds.

According to a 2002 US FDA survey, echinacea was the most used non-vitamin/non-mineral dietary supplement. Phytochemical constituents include caffeic acid derivatives, alkamides, glycoproteins, and polysaccharides. Generally, the polar and water-soluble polysaccharides have immune-stimulating properties, while the lipophilic alkamides have a powerful anti-inflammatory activity.