Echinacea purpurea, a plant used by native Americans to treat respiratory infections, was evaluated for its ability to stimulate the production of cytokines by normal human peripheral blood macrophages in vitro. The high levels of IL-1, tumor necrosis factor-a (TNF-a), and IL-10 induced by very low levels of Echinacea are consistent with an immune-activated group of herbaceous flowering plants in the daisy family, Asteraceae. The nine species it contains are commonly called coneflowers. Echinacea is a potent immune booster. E. purpurea is one of the most well-known medicinal plants in the world, belonging to the Asteraceae (composite) family. The plant is widely cultivated for its medicinal purposes in this species, which has been mainly used in chemopreventive and chemotherapy for infectious diseases in both upper and lower respiratory systems. This species has been used for the treatment of toothache, bowel pain, snake bite, skin disorders, seizure, chronic arthritis, and cancer. Alkamides, caffeic acid derivatives, and polysaccharides (PS) have been important constituents of the plant. Several studies revealed that alkamides are involved in the immunomodulatory properties of Echinacea extracts in vitro and in vivo. The PS play an important role in the anti-inflammatory effect. Taxonomic, chemical, pharmacological, and clinical characteristics of some species of the Echinacea genus include Echinacea angustifolia, Echinacea pallida, and E. purpurea are reviewed in previous papers. This paper is a review about E. purpurea, its phytochemical contents, and pharmacological and biological activities, along with the common methods of plant extract analysis which is reviewed in this review. In addition, the psychoactive and mosquitocidal effects of purpurea are mentioned in this paper.