The herb astragalus is also called huang qi and milk vetch. Astragalus extract is made from the root of the plant, which is native to Asia. In traditional Chinese medicine, this extract is often used to boost the immune system. The plant contains antioxidants, which strengthen the body's cells against damage.
While more research is needed, it is generally thought that astragalus extract works by stimulating the immune system to produce more white blood cells and antibodies. The herb contains antiviral, anti-inflammatory, and antibacterial properties. It is also an adaptogen, which are substances that can help the body cope with emotional or physical stress.
In addition to boosting the immune system, some people may take astragalus extract for general digestive health. Traditionally, it is also used for colds, the flu, and allergies, as well as infections. Some people may take it for anemia, stomach ulcers, and chronic fatigue, and conditions like mononucleosis. Astragalus extract may also be taken by patients with kidney or heart disease, and hepatitis. Patients should consider this herb to be complementary therapy, and not to be used in lieu of medical treatment.
Some preliminary studies have suggested that this herb may inhibit the growth of tumors. More research is needed in this area. Patients undergoing chemotherapy may use astragalus extract with the approval of a doctor. It may also help boost the appetite and relieve fatigue.
A typical dosage for an adult is a standardized extract of 250 to 500 milligrams (mg), taken three to four times per day. Doses higher than 25 grams (g) per day may actually suppress the patient's immune system. Adults taking a fluid extract, rather than a capsule, may take 2 to 4 milliliters (mL), three times daily. This recommendation is based on a 25% ethanol extract.
Parents and guardians should consult with a pediatrician before administering astragalus extract to a child. The doctor can provide a recommended dosage, as well as advice regarding long-term use. Children who have a fever should not take this herb.
Patients who have a medical condition, or those who are taking medications or other supplements, should consult with a physician before using an herb. Astragalus should not be taken by women who are pregnant or breastfeeding. People who have an autoimmune disease, as well as those who have had transplant surgery should avoid this substance. Astragalus may also interact with some medications, such as corticosteroids and drugs that suppress the immune system.