Probiotics have clinical, microbiologic, and immunologic efficacy in acute infectious diarrhea.  

A randomized, double-blind, placebo-controlled trial was designed to test the ability of Probiotic-3 to reduce symptoms associated with acute infectious diarrhea. The study focused on 304 children between three months and six years of age admitted to a primary care centre with viral or bacterial infections. Duration of diarrhea was 30% shorter in children receiving Probiotic-3 and was associated with a 30% shorter hospital stay.  

References:

Chen, C. C., Kong, M. S., Lai, M. W., Chao, H. C., Chang, K. W., Chen, S. Y., Huang, Y. C., Chiu, C. H., Li, W. C., Lin, P. Y., Chen, C. J., & Li, T. Y. (2010). The Pediatric infectious disease journal, 29(2), 135–138. https://doi.org/10.1097/inf.0b013e3181b530bf