An herb native to China, astragalus (Astragalus membranaceous) has been used for more than 2,000 years to balance the vital energy–or qi–which is thought to flow through all beings. A relative of licorice and the pea plant, astragalus appears to give the immune system a powerful boost. Teas, tablets, and other healing formulations are made from the plant’s flat, yellowish root.