Scientific support for use of astragalus is limited. There is a lack of high-quality research on the actual benefit of astragalus for any of its traditional uses. Some weak evidence exists to suggest that astragalus, either alone or in combination with other herbs, may have potential benefits for the immune system, heart, liver, and as an add-on therapy for cancer.
Use of astragalus is generally considered safe for most adults. However, possible side effects are not well known as the herb is usually used together with other ingredients.
This herb may interact with drugs that affect the immune system, such as chemotherapy for cancer and drugs taken by organ transplant recipients. Astragalus may also affect blood sugar levels and impact blood pressure.
Some astragalus species, not typically used in dietary supplements, can be toxic. For example, some species contain the neurotoxin swainsonine and have caused "locoweed" poisoning in animals. In addition, other species may contain potentially toxic levels of selenium (a dietary mineral).
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.