Native Americans traditionally used Echinacea to treat a variety of disorders, primarily where enhancement of the immune system was needed. Echinacea’s therapeutic efficacy was recognized by Western medical science in the late 19th century. Today, Echinacea is best known as a non-specific, immuno-supporting botanical. Laboratory and clinical studies have shown that Echinacea increases phagocytosis and stimulates lymphocyte activity in response to biological or physical stress. Preparations of Echinacea increase in vitro granulocyte and monocyte phagocytosis of Candida albicans by over 30%. It has been suggested that Echinacea stimulates the production of interferon, thus enhancing the functioning of macrophages, natural killer cells, and cytotoxic T cells. Often used in combination with other herbs, Astragalus has many uses, but is mostly known for its immune-stimulating properties. Numerous studies have indicated that Astragalus can have beneficial effects on the immune system by binding and activating B-cells and macrophages, stimulating lymphocytes and providing antioxidant activity. Nutrients such as garlic and zinc can also play important roles in the support of healthy immune function. Zinc is an essential trace element required for the activity of over 300 enzymes and is involved in most major metabolic pathways. Zinc participates not only in catalytic processes, but also in the structure and stability of some regulatory proteins.