Original Contribution

Functional GI Disorders

Multi-Center, Double-Blind, Randomized, Placebo-Controlled, Parallel-Group Study to Evaluate the Benefit of the Probiotic Bifidobacterium infantis 35624 in Non-Patients With Symptoms of Abdominal Discomfort and Bloating

  • The American Journal of Gastroenterology volume 112, pages 145151 (2017)
  • doi:10.1038/ajg.2016.511
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Bifidobacterium infantis 35624 is a probiotic that is used often in patients with irritable bowel syndrome (IBS). Non-patients with bowel symptoms may differ from patients with IBS in the impact of their bowel symptoms on illness severity, healthcare and treatment seeking behavior. The aim of this study is to assess the efficacy of B. infantis 35624 (109 c.f.u. per day) for the relief of abdominal discomfort and bloating in a non-patient population.


A double-blind, randomized, placebo-controlled, parallel study with a 2-week placebo run-in phase followed by a 4-week intervention phase was conducted at ten clinical centers (USA). Subjects were recruited from the general population by advertisement. The study randomized 302 subjects who experienced abdominal discomfort and bloating ≥2-times per week for at least three months but have not seen a physician or received prescribed medication for their symptoms in the past 12 months. Subjects were assessed for pre- to post-intervention changes in symptom severity (on a 6-point Likert scale; 0=none, 5=very severe) and frequency (symptoms-free days).


A total of 275 subjects (mean age 42 years, 79% female, 74% Caucasian) provided evaluable data. Overall mean severity scores at baseline were 2.4 for abdominal discomfort and 2.5 for bloating with no significant differences between the placebo and probiotic groups. Both groups showed significant (P<0.05) improvement in abdominal discomfort and bloating scores over the 4-week intervention period. Mean severity symptom scores at the end of intervention showed no significant differences between the probiotic and the placebo groups in either abdominal discomfort or bloating (P>0.3). The frequency of abdominal bloating-free days was greater in the B. infantis 35624 group compared to the placebo group (P<0.05). Both regimens were well tolerated.


Unlike previous clinical studies in patients with IBS, B. infantis 35624 did not show a significant improvement in the mean severity of symptoms of abdominal discomfort and bloating in a non-patient population. This may be explained by the high placebo effect and the lower impact of functional bowel symptoms in the non-patient population.

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This study was sponsored by P&G. ClinicalTrials.gov number NCT01099696.

Author information


  1. Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA

    • Tamar Ringel-Kulka
  2. The Procter & Gamble Company, Mason, Ohio, USA

    • Johnson McRorie
  3. School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA

    • Yehuda Ringel
  4. Department of Gastroenterology, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel

    • Yehuda Ringel


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Competing interests

Guarantor of the article: Johnson McRorie, PhD.

Specific author contributions: Planning: Y.R. and J.M.; and/or conducting the study: Y.R. and T.R.K.; collecting: Y.R., T.R.K.; and/or interpreting data: Y.R., T.R.K., and J.M.; and/or drafting the manuscript: Y.R., T.R.K., and J.M.. Y.R. has approved the final draft submitted. T.R.K. has approved the final draft submitted. J.M. has approved the final draft submitted.

Financial support: This multi-site study was sponsored by P&G. The sponsor was responsible for the study design, protocol, data collection and analysis. Study sites were responsible for conduction of the study and assuring data collection according to protocol. The co-authors were responsible for interpretation of the data and writing of the report.

Potential competing interests: Dr R.-K. has received research funding from P&G. J.M. is a full-time employee of P&G, which markets probiotics. Y.R. and T.R.K. received research funding and Y.R. received consultation honorarium from P&G.

Corresponding author

Correspondence to Yehuda Ringel.