This trial employed a multicenter, randomized, double-blind, parallel, placebo-controlled design to evaluate the preventive effect of BPR-101 capsules combined with metronidazole on the recurrence of BV, as well as the cure rate and safety.

Inclusion Criteria:

1. Females aged ≥18 years and ≤50 years, of childbearing age with a history of sexual activity;
2. Clinically diagnosed with Bacterial Vaginosis (BV), this test requires meeting at least 3 of the following 4 Amsel criteria (with a positive clue cell test being a mandatory condition): positive clue cells; positive amine test; vaginal discharge pH > 4.5; and Vaginal discharge is homogeneous, thin, and grayish-white in appearance；
3. Nugent score ≥ 7 points；
4. Vaginal administration is acceptable, and the patient agrees to avoid using any other vaginal products (such as contraceptive creams, gels, foams, sponges, lubricants, douches, tampons, etc.) except as specified in the trial throughout the entire trial period；
5. Researchers have assessed that the menstrual cycle is regular;
6. Subjects must voluntarily sign a written informed consent form before the trial, understand the procedures and methods of the trial, and be willing to strictly abide by the clinical trial protocol and complete the trial.

Exclusion Criteria:

1. Currently suffering from pelvic inflammatory disease, acute cervicitis, and urinary tract infection requiring intervention, among other acute infections of the genitourinary system;
2. Presence of vulvovaginitis caused by other pathogens, which researchers considered to affect trial evaluation, such as aerobic vaginitis (AV), vulvovaginal candidiasis (VVC), and trichomoniasis；
3. Currently, other vaginal or vulvar diseases are considered by researchers to affect the evaluation of the trial, such as human papillomavirus infection; or gynecological examinations showing condyloma acuminata or genital herpes；
4. Unexplained abnormal vaginal bleeding within 6 months prior to screening or during the screening visit;
5. Those who currently have uterine fibroids, endometrial hyperplasia, endometriosis, or adenomyosis, and for whom researchers believe that intervention is necessary during the trial;
6. Received local or systemic antifungal or antibiotic treatment or probiotic treatment within 2 weeks prior to screening; or vaginal douching or other vaginal treatments (such as Jieeryin, Jieyinkang, etc.) within 1 week prior to screening, and/or expected to receive the above treatments during the trial;
7. Used systemic steroids (oral or injectable), disulfiram, lithium salts within 14 days prior to screening., and/or expected to receive such treatment during the trial;
8. Currently using and/or expected to require cimetidine, warfarin (or other anticoagulation therapy) during the trial;
9. Products containing alcohol or propylene glycol that are expected to be used within 3 days prior to screening and/or during the trial period;
10. Hhistory of malignant tumors within 5 years prior to screening and deemed unsuitable for inclusion by the researchers, except for those with adequately treated basal cell carcinoma or squamous cell carcinoma of the skin and cervical carcinoma in situ;
11. Hhistory of major gynecological surgery within 6 months prior to screening(deep wounds, long recovery time), or superficial gynecological surgery or common procedures within 60 days prior to screening，or whose screening visit is within 60 days of their last termination of pregnancy;
12. History of or currently suffering from serious diseases of the cardiovascular, liver, kidney, lung, digestive tract, nervous and mental system, genitourinary system, endocrine system, etc., and are deemed unsuitable for inclusion by the researchers;
13. Laboratory tests meeting any of the following criteria, and the investigator deems them unsuitable for inclusion: serum creatinine > 1.5 times the upper limit of normal (ULN); urea/urea nitrogen > 1.5 ULN; alanine aminotransferase (ALT) > 2 ULN; aspartate aminotransferase (AST) > 2 ULN;
14. Known hypersensitivity to any component of BPR-101 capsules or to other similar drugs (such as Live Lactobacillus Capsule for Vaginal Use ); or nitroimidazole, metronidazole, or any of the excipients；
15. Women who are pregnant or breastfeeding, or whose pregnancy test results are positive, or who plan to become pregnant throughout the trial and within 3 months after the last dose; or who cannot accept the use of reliable contraception (absence of sexual intercourse or barrier contraception with condoms throughout the study period);
16. Participated in other drug or device clinical trials within 1 month prior to screening and have used the investigational drug or device;
17. The researchers believe that the subject has any other circumstances that would make them unsuitable to participate in the trial.

This study only included female participants.