In Asia, this plant is sold as dried slices of root, six to twelve inch long. Research has shown that this root and its extracts are powerful stimulators of the immune system. Astragalus has been used for thousands of years in China. Some of the specific Chinese uses hint at a stimulant effect on the immune system. For example, it used as a tonic for the lungs, for frequent colds or shortness of breath.
Astragalus stimulates virtually every phase of immune system activity.
The remedy also decreased negative side effects of steroid therapy on the immune system. Perhaps the best evidence to date for the powerful immunostimulant effects of astragalus come from the University of Texas Medical Center in Houston. There, scientists tested damaged immune system cells from cancer patients, compared against cells from the blood of normal human subjects. In some cases, the compromised cells were stimulated to greater activity than those from normal human subjects. Astragalus has also been found to stimulate the production of interferon, and increase its effects in fighting disease.