Endometriosis (EMs) is one of the most prevalent benign gynaecological diseases, and it is an inflammatory oestrogen-dependent condition. Several authors have proposed that anatomical, genetic, endocrine, immunological, environmental, hormonal, and inflammatory factors may influence tissue implantation outside the uterus. An approach to EMs aetiology that involves defining a profile to the vaginal and gut microbiota, estrogenic activity, and exposure to xenoestrogens and also metabolic and nutritional status of women with EMs may help identify some important patterns to better characterize this disease and also to define more personalized nutritional strategies, also predicting patients' predisposition to therapy success. This is an observational study on premenopausal woman, diagnosed with EMs, who will be recruited on the outpatient gynaecology appointment, to evaluate the vaginal and intestinal microbiome, measure the total estrogenic activity, assess the metabolic biomarkers and the nutritional status.

Inclusion Criteria:

• Premenopause;
• Diagnose of endometriosis by clinical and/or imaging criteria (associated adenomyosis is accepted);
• BMI between 18.5 and 30.0 kg/m2

Exclusion Criteria:

• Postmenopause;
• Vegetarian diet;
• Pregnancy or breastfeeding;
• Continuous hormonal therapy for endometriosis;
• Laparoscopic surgery for endometriosis purpose;
• Gastrointestinal or vaginal infections;
• Intaken antibiotics and/or probiotics within the last 8 weeks;
• Medications to treat vaginal infections in the past 3 months.

Any premenopausal woman diagnosed with endometriosis under an outpatient gynaecology appointment at one of the recruitment locations.