For more than 2,000 years, Chinese herbalists have valued astragalus for its adaptogenic properties, as well as for its ability to tonify the body's "vital force" known as the Qi. More recently, astragalus has been found to support healthy immune function through numerous mechanisms. Astragalus has also been studied for its role in the support of healthy liver and vascular function. Herbalists recommend the use of astragalus both seasonally and year-round to support a healthy immune system.