Lactobacillus species are probiotics frequently considered as adjuncts to antibiotic therapy, primarily to reduce side effects like antibiotic-associated diarrhea and to help restore normal gut flora disrupted by antibiotics. However, the use of Lactobacillus as a direct alternative to antibiotics for treating infections is not broadly supported by scientific evidence. The main evidence relates to their supportive role rather than as replacements.

Several randomized controlled trials and meta-analyses indicate that certain Lactobacillus strains (e.g., L. rhamnosus GG, L. reuteri) can reduce the incidence and severity of antibiotic-associated diarrhea and Clostridioides difficile infection, especially in children. These findings have led to moderate recommendations for their adjunctive use, particularly in vulnerable populations.

However, the evidence for Lactobacillus as a true alternative to antibiotics for treatment of infections is limited. Most studies do not support the efficacy of Lactobacillus alone in treating bacterial infections that would otherwise require antibiotic therapy. Current guidelines do not recommend substituting antibiotics with probiotics for the management of active infections.

In summary, scientific evidence supports the adjunctive use of Lactobacillus with antibiotics to mitigate side effects and restore microbiota, but not as stand-alone alternatives to antibiotic therapy.