Known in China as a 'Qi' tonic, astragalus is one of the most beneficial immune tonics. It increases the body's resistance to disease, strengthens the digestion, and improves the vitality of the immune system. Astragalus increases the 'bone marrow reserve', enabling the body to produce more immune effector cells {such as t-cells}, aiding the immune system in its fight against pathogens. In China, health practitioners prescribe astragalus as a daily tonic. Astragalus is often blended with other immune tonics like ligustrum.