Abstract

Summary Background : Irritable bowel syndrome is a gastrointestinal disorder of unknown aetiology. The effect of probiotics in this syndrome remains unclear. Aim : To investigate whether a probiotic mixture containing Lactobacillus rhamnosus GG, L. rhamnosus LC705, Bifidobacterium breve Bb99 and Propionibacterium freudenreichii ssp. shermanii JS is effective in alleviating irritable bowel syndrome symptoms. Methods : A total of 103 patients fulfilling the Rome I or II criteria took part in this 6‐month, randomized, double‐blind placebo‐controlled trial. The patients received a probiotic capsule or a placebo capsule daily. Gastrointestinal symptoms and bowel habits were recorded. Results : At the end the total symptom score (abdominal pain + distension + flatulence + borborygmi) was 7.7 (95% CI: −13.9 to −1.6) points lower in the probiotic group ( P = 0.015). This represents a median reduction of 42% in the symptom score of the probiotic group compared with 6% in the placebo group. In individual symptoms, borborygmi was milder in the probiotic group ( P = 0.008), and for the rest of the symptoms there was a non‐significant trend. Conclusions : The results indicate that this probiotic mixture is effective in alleviating irritable bowel syndrome symptoms. Considering the high prevalence of irritable bowel syndrome and the lack of effective therapies, even a slight reduction in symptoms could have positive public health consequences.