This all points to the conclusion that its actions relate to immune system functioning on some level, helping deal with infections and stimulating the immune response. It activates the macrophages that destroy both cancerous cells and pathogens, increases the level of phagocytosis by raising levels of white blood cells such as the neutrophils, monocytes, eosinophils, and B lymphocytes. It also has an effect on properidin levels, indication an activation of the complement system.

Preparations & Dosage: Decoction: put 1-2 teaspoonfuls of the root in one cup of water and bring it slowly to boil. Let it simmer for 10-15 minutes. This should be drunk three times a day. Tincture: take 1-4 ml of the tincture three times a day. Echinacea is often, inappropriately, used as a daily `immune support' (whatever that is!). A quote from Dr. Daniel Mowrey's excellent review of Echinacea in Next Generation Herbal Medicine is pertinent here:

"Daily intake should be restricted to what is deemed necessary. During cold and flu season, two to four capsules per day is sufficient. In the presence of acute infection, that dosage may be increased, without danger, to more than 8 capsules. In the presence of chronic infections, such as chronic hepatitis, echinacea may be used continuously for several months. However, for the maintenance of a healthy immune system, echinacea is most wisely used periodically--a few weeks on, and a few weeks off, throughout the year. Echinacea is not a tonic in all aspects; granted that it has been observed to stabilize the production of neutrophils, such tonic action has not been observed on other immune factors, such as properdin production. In the absence of conclusive experimental findings, it is both safe and wise to assume that the constant, unremitting use of echinacea could be stressful on certain aspects of the immune system. During breaks, the immune system will adapt and increase in natural strength."

Citations from the Medline database for the genus Echinacea

Echinacea Bauer R Foster S Analysis of alkamides and caffeic acid derivatives from Echinacea simulata and E. paradoxa roots.

Planta Med 1991 Oct;57(5):447-9 Bauer VR Jurcic K Puhlmann J Wagner H [Immunologic in vivo and in vitro studies on Echinacea extracts]

Arzneimittelforschung 1988 Feb;38(2):276-81 (Published in German)

Ethanolic extracts of Echinacea purpurea, E. pallida and E. angustifolia roots were examined for immunological activity in the carbon clearance test with mice and in the granulocyte test. In the in vivo experiment all extracts, administered orally, were found to enhance phagocytosis significantly. These results correlate with the stimulation of phagocytosis in the in vitro granulocyte test. The lipophilic fractions of the extracts appeared to be more active than the polar fractions. All extracts were analyzed by HPLC in order to correlate the chemical constituents with the immunological activities. Coeugniet EG Elek E Immunomodulation with Viscum album and Echinacea purpurea extracts.

Onkologie 1987 Jun;10(3 Suppl):27-33

Extracts of Viscum album (Plenosol) and Echinacea purpurea (Echinacin) are used clinically for their non-specific action on cell- mediated immunity. In vitro we could prove that these two extracts have a stimulating effect on the production of lymphokines by lymphocytes and in the transformation test. A toxic effect on cells was produced only with very high, clinically irrelevant concentrations. Clinical application of these extracts can produce a stimulation of cell-mediated immunity (one therapeutic administration followed by a free interval of one week) or can have a depressive action (daily administrations of higher doses). These observations were confirmed by lymphokine production and assay, 3H-thymidine incorporation and a skin test with recall antigens (Multitest Merieux). Gaisbauer M Schleich T Stickl HA Wilczek I [The effect of Echinacea purpurea Moench on phagocytosis in granulocytes measured by chemiluminescence]