probiotic vs. placebo in irritable bowel syndrome: a randomized controlled trial

background this study assesses the potential effect of lactobacillus reuteri as a single strain probiotic preparation (biogaia®) on irritable bowel syndrome (ibs). methods patients diagnosed with ibs who fulfilled rome iii criteria and consented to participate in this study were randomized to receive either the probiotic or an identical placebo once daily for four weeks. patients used a questionnaire to record any symptoms and adverse reactions over a one-week run-in period and during the final two weeks of intervention. for each group, we calculated the differences between mean scores of the variables and compared the results between groups. results frequency of defecation increased in the biogaia® group and decreased in the placebo group meaningfully. but there were no significant difference in the two groups in other terms of bloating, sense of urgency for defecation, abdominal pain, stool shape, quality of defecation, sense of incomplete evacuation, and treatment satisfaction. conclusion the frequency of defecation increased in the biogaia® group and decreased in the placebo group, however this study did not classify patients according to diarrhea or constipated subgroups, the efficacy of this drug is not clear. hence lactobacillus reuteri was not better than placebo in controlling ibs symptoms in this study. however, considering the significant placebo effect in ibs patients, it may be necessary to conduct studies with larger numbers of participants to better assess the possible beneficial effects of biogaia.