Across 3 studies, 2 reported beneficial effects, including a large-sized reduction in crying duration (WMD -51.3 h, CI95% -72.2 to -30.5 h, P < 0.0001) from a systematic review of 2242 infants with colic, while one small neutral RCT showed no statistically significant benefit in antibiotic-exposed neonates. The predominant effect size is large in the most robust study, but evidence is limited by the small number of studies. Effects were observed in infants with colic, with a median study duration of 42 days.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. The beneficial findings are driven by one high-quality systematic review; the only RCT (n=89) did not achieve statistical significance, suggesting the effect may be less consistent in certain populations (e.g., antibiotic-exposed neonates). The beneficial review (2025) is low-quality (evidence score 1) and provides limited independent support.
L reuteri DSM 17938 [WMD -51.3 h (CI95% -72.2 to -30.5 h), P .0001]
the probiotic group presented a longer sleep duration and shorter crying time than the control group, but the difference was not statistically significant.
for breastfed infants, Lactobacillus reuteri DSM 17938 is associated with fewer crying minutes