To date, few studies have addressed the link between gut microbiota and breast cancer chemotherapy, and previous studies have only provided a link between the gut and breast cancer.

To date, few studies have addressed the link between gut microbiota and breast cancer chemotherapy, and previous studies have only provided a link between the gut and breast cancer.At present, studies on the interaction mechanism between intestinal flora and breast cancer mainly focus on two aspects: first, intestinal flora affects the occurrence and progress of breast cancer by affecting estrogen metabolism;Second, intestinal flora can influence the occurrence and treatment of breast cancer by affecting the regulation of the immune system.However, the specific types (or groups) of bacteria that promote the occurrence, development and mechanism of breast cancer still need to be further studied.In addition, since most of the current clinical studies on microorganisms and breast cancer are small sample studies, the accuracy of their conclusions remains to be studied.

Inclusion Criteria:

• Aged 18 to 65 years
• First use of chemotherapy after breast cancer

Exclusion Criteria:

• Pregnancy
• Lactation
• Cigarette smoking
• Alcohol addiction
• Hypertension
• Diabetes mellitus
• Lipid dysregulation
• BMI > 27
• Recent (< 3 months prior) use of antibiotics, probiotics, prebiotics, symbiotics, hormonal medication, laxatives, proton pump inhibitors, insulin sensitizers or Chinese herbal medicine
• History of disease with an autoimmune component, such as MS, rheumatoid arthritis, IBS, or IBD
• History of malignancy or any gastrointestinal tract surgery

All patients were included according to the inclusion and exclusion criteria