This is a national, multi-centre, randomized, double-blind placebo-controlled, phase III superiority trial.

The main objective of the trial is to assess the efficacy of Lcr35® by comparing the mean time before the onset of the first clinical recurrence confirmed by laboratory tests in patients with bacterial vaginosis treated with Lcr35® versus placebo.

Patients with bacterial vaginosis will be enroll by private gynecologists. Each patient will receive a treatment for the initial episode(Metronidazole)and a treatment to prevent the recurrence of bacterial vaginosis (Lcr35®).

Inclusion Criteria:

• Patient presenting with a symptomatic vaginosis characterised by the presence of the following 3 clinical criteria (among the 4 Amsel criteria) at V1:

  • greyish uniform vaginal discharge,
  • characteristic "rotten fish" smell caused by the spontaneous release of amine or during the potassium test or "sniff test",
  • vaginal pH greater than 4.5.

• Patient with a Nugent score ≥ 7 (using the sample taken at V1).

• Patient clinically cured (none of the 3 Amsel criteria) after a 7-day course of Metronidazole (Flagyl®) Female.

• Patient over 18 years of age.

• For women with childbearing potential:

  • negative urine pregnancy test,
  • use of a contraceptive method deemed effective by the Investigator (excluding spermicides).

• Patient having received information and voluntarily signed a written Informed Consent Form.

• Patient covered by a national insurance scheme.

Exclusion Criteria:

• Presence of a yeast infection that is bacterial (other than vaginosis) or viral in origin presumed or proven to be gynaecologically-linked, whether or not treated within the month preceding inclusion or present at the time of inclusion.
• Presence of an existing gynaecological infection that may interfere with the assessment of the trial treatment(fibroma, severe dysplasia of the cervix or in situ carcinoma, invasive carcinoma, intra-epithelial cervical neoplasia, squamous intra-epithelial lesions etc.)
• Antibiotics or antifungals taken by general route during the month preceding the screening visit, excluding treatment for an earlier episode of vaginosis.
• Use of probiotics in the month preceding the screening visit, excluding treatment for an earlier episode of vaginosis.
• Use of intravaginal antiseptics in the month preceding the screening visit, excluding treatment for an earlier episode of vaginosis.
• Use of prebiotics (acidifiers) during the two weeks preceding the screening visit.
• Use of products containing topical oestrogens during the month preceding the screening visit.
• Allergy to one of the active ingredients or one of the excipients in the products.
• patient in post-menopausal time
• Patient unable to comply with the constraints of the Protocol.
• Breastfeeding patient.
• Patient with menstrual bleeds lasting more than 12 days a month.
• Patient having taken part in a clinical trial in the 3 months preceding inclusion in the present Protocol.
• Patient with a severe acute or chronic disease deemed by the Investigator to be incompatible with participation in the trial, or a serious infection that is life-threatening in the short term.
• Immuno-suppressed patient.
• Patient presenting with a previous illness which, according to the Investigator, is likely to interfere with the results of the trial or expose the patient to an additional risk.
• Patient linguistically or mentally unable to understand and sign the Informed Consent Form.
• Patient deprived of her liberty by order of the Courts or civil authorities or subject to a guardianship order.
• Patient likely not to comply with treatment.
• Patient unable to be contacted in the case of an emergency.