To explore the effect of astragalus injection in assisting post-chemotherapy gastrointestinal side effects and nutritional status in patients with breast cancer.Methods：Divided 83 cases of post-chemotherapy patients with breast cancer into two groups randomly，41 cases in the control group and 42 cases in the observation group.The control group received pIacebo based on chemotherapy，while the observation group received astragalus injection based on chemotherapy.Compared the changes in gastrointestinal side effects，toxic reactions and quality of life after treatment as well as nutritional status before and after treatment of patients in both groups.Results：The incidence of adverse reactions was 36.59%in the control group and 9.52%in the observation group，difference being significant(P ＜ 0.05).After treatment，comparing WBC in both groups，there was no significant difference being found(P＞0.05).Comparing Hb and BPC in both groups，there was significant difference being found(P ＜ 0.05).After treatment，the skinfold thickness of triceps，waist circumference，body mass in the observation group were better than those in the control group，difference being significant(P ＜ 0.05).The scores of mental health，emotional function，physiological function，mental state，activity ability，bodily pain，social function and ove rall health in the observation group were significantly better than those in the control group，difference being significant(P＜0.05).Conclusion：Astragalus injection in assisting chemotherapy for breast cancer can effectively reduce gastrointestinal side effects and toxic reactions of patients，sustain their nutritional status and promote the quality of life.