The present study conducted a meta-analysis and systematic review of current evidence to assess the efficacy of probiotics in preventing or treating small intestinal bacterial overgrowth (SIBO). Relevant studies from PubMed, Embase, and the Cochrane Central Register of Controlled Trials, until May 2016, were assimilated. The prevention efficacy was assessed by the incidence of SIBO in the probiotic group, and the treatment efficacy by the SIBO decontamination rate, reduction in H-2 concentration, and symptom improvement. The relative risk (RR) and weighted mean difference (WMD) were used as effect measures and the random-effects model used for meta-analysis. A total of 14 full-text articles and 8 abstracts were included for the systematic review, and 18 studies were eligible for data synthesis. Patients on probiotic usage showed an insignificant trend toward low SIBO incidence [RR=0.54; 95% confidence intervals (CI), 0.19-1.52; P=0.24]. The pooled SIBO decontamination rate was 62.8% (51.5% to 72.8%). The probiotics group showed a significantly higher SIBO decontamination rate than the nonprobiotic group (RR=1.61; 95% CI, 1.19-2.17; P< 0.05). Also, the H2 concentration was significantly reduced among probiotic users (WMD= - 36.35 ppm; 95% CI, - 44.23 to - 28.47 ppm; P< 0.05). Although probiotics produced a marked decrease in the abdominal pain scores (WMD=- 1.17; 95% CI, - 2.30 to - 0.04; P< 0.05), it did not significantly reduce the daily stool frequency (WMD=- 0.09; 95% CI, - 0.47 to 0.29). Therefore, the present findings indicated that probiotics supplementation could effectively decontaminate SIBO, decrease H-2 concentration, and relieve abdominal pain, but were ineffective in preventing SIBO.