Nonpuerperal mastitis (NPM), mainly including Plasma cell mastitis (PCM) and Granulomatous mastitis (GM), which clinical presentation is an accessible and painful breast mass accompanied by skin redness and swelling, nipple retraction and fistula formation . Much progress has been made in exploring the etiology and pathogenesis of NPM, while the exact etiology remains unknown, NPM is thought to arise from interactions between genetic susceptibility factors, epigenetic effects, and various environmental factors. While microbiota as an environment factor to some inflammatory and autoimmune diseases accept widespread attention, if gut microbiota also as a risk factor for NPM, it is worthy to be considered.

NPM is common in young women of reproductive age with a history of lactation and childbearing . The main clinical presentation is an accessible and painful breast mass accompanied by skin redness and swelling, nipple retraction and fistula formation

. The imaging of NPM is not specific, with NPM mimicking breast cancer in imaging . NPM etiology is associated with several factors, such as autoimmunity, bacterial infections , estrogen and progesterone imbalance , and hyperprolactinemia . In recent years, NPM has become a common benign breast disease, especially in the Mediterranean region and developing countries in Asia, such as China . Currently, the associations between bacterial infections and NPM are among the important issues attracting research interest. This study tried to reveal the roles of gut microbiota in NPM. Further understanding of the roles of gut microbiota in this disease may lead to the development of methods for personalized therapy.

Inclusion Criteria:

• Aged 18 to 65 years
• Patients of NPM

Exclusion Criteria:

• Pregnancy
• Lactation
• Cigarette smoking
• Alcohol addiction
• Hypertension
• Diabetes mellitus
• Lipid dysregulation
• BMI > 27 <18.5
• Recent (< 1 months prior) use of antibiotics, probiotics, prebiotics, synbiotic, hormonal medication, laxatives, proton pump inhibitors, insulin sensitizers or Chinese herbal medicine
• History of disease with an autoimmune component, such as multiple sclerosis(MS), rheumatoid arthritis, irritable bowel disease(IBS), or irritable bowel syndrome(IBD)
• History of malignancy or any gastrointestinal tract surgery

Study Population are aged from 18 to 65 years#which divided into 2 groups: NPM group and Control group