The use of Lactobacillus (mixed) for the support or treatment of vaginitis is supported by a moderate level of scientific evidence. The rationale is based on the observation that a healthy vaginal microbiome is typically dominated by Lactobacillus species, which help maintain an acidic environment through lactic acid production, thereby inhibiting the growth of pathogenic organisms associated with vaginitis, such as Gardnerella vaginalis and Candida species.

Several randomized controlled trials and meta-analyses have investigated the effectiveness of oral and intravaginal Lactobacillus probiotics in preventing and treating bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC), two common forms of vaginitis. Some studies have shown a modest benefit, particularly when probiotics are used as an adjunct to standard antimicrobial therapy, leading to higher cure rates and reduced recurrence. However, results are variable depending on the specific strains used, dosage, and route of administration. Systematic reviews (e.g., Huang et al., 2014, PLoS One; Senok et al., 2009, Cochrane Database Syst Rev) generally conclude that probiotics containing Lactobacillus can be beneficial, but the evidence is not uniformly strong, and optimal formulations are still under investigation.

In summary, there is scientific rationale and moderate clinical evidence supporting the use of mixed Lactobacillus strains for certain forms of vaginitis, but more high-quality studies are needed to define best practices.