Danggui Buxue Tang (DBT), a combination of Astragalus and Angelica at a 5 : 1 ratio, mainly promotes hematopoiesis. However, in the clinic, the combination ratio of Astragalus and Angelica to treat low hematopoietic function is not an absolute 5 : 1 ratio, suggesting that the herbs may promote hematopoiesis better after being combined at a certain range of ratios. The objective of this study is to investigate the effect of different ratio combinations of Astragalus and Angelica on bone marrow hematopoiesis suppression induced by cyclophosphamide (CTX) and to probe the interaction and mechanism...