Immune system support supplement - For more than 2,000 years, Chinese herbalists have evaluated Astragalus for its adaptive properties. Recently, it has been discovered that astragalus improves immune function through various mechanisms, and help prevent infections in people who has weak immune system as well as healthy ones who want extra protection. The content of Polysaccharides in Sthina products is not less than 40%,  which provide best quality assurance.