Astragalus is an herb and mainly taken to stimulate and increase the immune system

Astragalus is used for the common cold, upper respiratory infections, allergies, fibromyalgia, anemia, HIV/AIDS, and to strengthen and regulate the immune system. It is also used for chronic fatigue syndrome (CFS), kidney disease, diabetes, and high blood pressure.

A popular use for astragalus is to support energy level during glandular fever.