Despite claims that astragalus (a herb commonly used in traditional Chinese medicine) can boost the immune system, evidence is limited. There is some evidence from animal studies, but high quality clinical trials (studies in people) are lacking. Astragalus has been used for over two thousand years, and has been used by western herbalist practitioners since the 1880s. Proponents claim that when used by itself or in combination with other herbs, astragalus can benefit the immune system by aiding the body’s antibody responses, inhibiting tumour growth. They also suggest that astragalus can help cancer patients cope with physical and emotional stressors, as well as boost the body’s resistance to fight off infections. While there is no scientific proof to support these claims, there is more convincing evidence that astragalus can help reduce side-effects of chemotherapy, such as nausea and vomiting. If you are considering taking this herb, we recommend you talk to your treating oncologist, particularly to check whether it may interact with your cancer treatment.