Echinacea, Astragalus and Grapefruit Seed Extract. Echinacea has traditionally been used for its antibiotic, antiviral and anti-inflammatory properties. It is also excellent as an immune system support. Astragalus, though not as well known in the West as Echinacea, is prized by practitioners of Oriental medicine for its role in immune system enhancement and support of the adrenal, respiratory and digestive systems. It promotes healing and provides energy to combat fatigue. The Power of 3 combines the beneficial properties of both herbs and grapefruit seed extract for excellent immune system support.