The characteristics required of lactobacilli as probioties are the following: beneficial function, easy cultivation, nonpathogenicity, adhesion, and population stability. Several studies have assessed the potential of lactobacilli in the prevention or treatment of certain genitourinary tract infections such as bacterial vaginosis, vaginitis, or urinary tract infections. The main goal of therapy with biotherapeutic agents should be to prevent overgrowth of a pathogen until such a time that the normal microbiota can be reestablished. The possibility of using lactobacilli is promising, especially in pregnant women and in the case of patients with recurrent genitourinary tract infections produced by strains with resistance to several antibiotics. In addition, probiotic therapy is considered as "natural" and without side effects in contrast with conventional pharmaceutical treatments, but there is a limited array of tested biotherapeutic agents and a lack of pharmacokinetic data.