Lactobacillus rhamnosus is a probiotic bacterium that has been studied for its role in supporting the female reproductive system, particularly in maintaining vaginal health. Scientific evidence suggests that L. rhamnosus can help restore and maintain the normal vaginal microbiota, which is crucial for protecting against infections such as bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC). Several clinical trials and reviews have demonstrated that oral or intravaginal administration of L. rhamnosus, alone or in combination with other Lactobacillus strains, may reduce the recurrence of BV and yeast infections by competitively inhibiting pathogenic microbes, producing lactic acid (which lowers vaginal pH), and enhancing the local immune response.

A 2014 Cochrane review and various more recent studies have found that L. rhamnosus GR-1, especially when combined with L. reuteri RC-14, is effective in re-establishing a healthy vaginal flora. The use of these probiotics has been associated with increased cure rates and decreased recurrence of vaginal infections compared to placebo. However, while the evidence base is increasingly robust, not all studies are positive and some heterogeneity in outcomes exists depending on population, probiotic strain, and administration route. Overall, the use of L. rhamnosus for female reproductive health is supported by a growing body of scientific literature and is considered an evidence-based adjunct to conventional therapy for vaginal infections.