Objective To explore the effect of nutritional therapy based on anti-inflammatory diet in breast cancer chemotherapy patients and its effects on inflammatory indicators intestinal gate level dominant flora and adverse events. Method A total of 228 breast cancer chemotherapy patients admitted to Qinhuangdao Second Hospital from February 2021 to February 2024 were selected as the study objects They were divided into two groups according to the random number method. 114 patients in the control group received routine nutritional support and 114 patients in the observation group received nutritional treatment based on anti-inflammatory diet. Compare the inflammatory factor levels leukocyte- 1β IL- 1β tumor cytokines TNF - α C reactive protein CRP immune function CD8 + T cells CD4 + T cells CD3 + T cells nutritional status index body mass index BMI upper arm circumference MAC triceps skinfold thickness TF serum nutrition index prealbumin PA albumin Alb total protein TP dominant flora Firmicutes antibacteria AFP at the same time The occurrence of adverse events during hospitalization was statistically analyzed in two groups. Result After 14 days of intervention the levels of IL-1 β TNF - α CRP CD8 + T cells BMI MAC TSF and the logarithm of Firmicutes and Actinobacteria in both groups were lower than before intervention. The levels of CD4 + T cells CD3 + T cells PA Alb TP and the logarithm of Bacteroidetes and Actinobacteria were higher than before intervention in the same group and the differences were statistically significant P < 0. 05 . At the same time after 14 days of intervention the intervention group showed better improvement in IL-1 β TNF - α CRP CD8 + T cells CD4 + T cells CD3 + T cells PA Alb and TP compared to the control group and the difference was statistically significant P<0. 05 . BMI MAC TSF and the composition of Firmicutes and Actinobacteria were lower in the intervention group compared to the control group and the difference was statistically significant P<0. 05 . The composition of Bacteroidetes and Actinobacteria was higher in the intervention group compared to the control group and the difference was statistically significant P<0. 05 . Meanwhile the adverse events in the intervention group 6. 14% vs 14. 91% were lower than those in the control group and the difference was statistically significant P<0. 05 . Conclusion Nutritional therapy based on anti-inflammatory diet is more feasible safe and scientific. It is used in breast cancer chemotherapy patients to better reduce inflammation improve body immune function improve nutritional status and promote the overall health recovery. It is of great significance for clinical treatment guidance and prognosis improvement and has high utilization value.