To maintain a healthy vaginal ecosystem or to restore any disturbance, sufficient estrogen levels, an intact mature vaginal epithelium, and physiological lactobacillary microflora are essential. Thus, a combination of beneficial lactobacilli and estrogen is an appealing treatment option. This article reviews the published data on the use of viable Lactobacillus acidophilus KS400 and a low dose of estriol (0.03 mg E3) in the form of vaginal tablets (Gynoflor®). In vitro studies demonstrated that L. acidophilus KS400 produces lactic acid and hydrogen peroxide (H2O2), inhibits the growth of relevant vaginal pathogens, and inhibits adherence of pathogens to epithelial cells. Topical administration of E3 for treatment of vaginal diseases is generally preferred, as this route of application of hormones produces a more significant local proliferative response and has no stimulating effect on the endometrium. Overall, 16 clinical studies have been published with the combination of L. acidophilus KS400 and 0.03 mg E3. The results of these trials have demonstrated that the combination improves the vaginal epithelium and the restoration of the lactobacillary microflora with an excellent safety profile, even during pregnancy. The combination can be used in pre- and postmenopausal women for the restoration of the vaginal flora after anti-infective therapy, for treatment of symptomatic vaginal atrophy, and for abnormal vaginal flora therapy. It can be also considered in repetitive therapy courses for the long-term prevention of recurrences of bacterial vaginosis, even though further clinical studies are needed to substantiate the benefit of this application.

Keywords: Lactobacillus acidophilus, estriol, abnormal vaginal flora, restoration of vaginal ecosystem, recurrence prevention, vaginal atrophy