Article Text

Original research
Probiotics for the prevention of antibiotic-associated diarrhoea: a systematic review and meta-analysis
  1. Clare Goodman1,
  2. Georgia Keating2,
  3. Ekavi Georgousopoulou1,
  4. Charlotte Hespe1,
  5. Kate Levett1
  1. 1National School of Medicine, The University of Notre Dame Australia, Sydney, New South Wales, Australia
  2. 2Department of Pharmacy, Alice Springs Hospital, Alice Springs, Northern Territory, Australia
  1. Correspondence to Dr Clare Goodman; kate.levett{at}


Objective To evaluate existing evidence for the use of probiotics in preventing antibiotic-associated diarrhoea (AAD) in adults.

Design Systematic review and meta-analysis of randomised controlled trials (RCTs).

Data sources We performed a literature search of the electronic databases CINAHL Plus, EMBASE, MEDLINE (Ovid) and Web of Science from database inception to May 2021 as well as hand searching of trial registries and reference lists of related reviews.

Study selection Two reviewers identified whether RCTs met the following inclusion criteria: adult population to whom antibiotics were administered; a probiotic intervention; a placebo, alternative dose, alternative probiotic strain or no treatment control; and incidence of AAD as the outcome.

Data extraction and synthesis Two reviewers independently collected data and assessed risk of bias using preconstructed data extraction forms. We used a random effects model for all analyses. Subgroup analyses were performed to evaluate species-specific and dose-specific response.

Results Forty-two studies (11,305 participants) were included in this review. The pooled analysis suggests that co-administration of probiotics with antibiotics reduces the risk of AAD in adults by 37% (risk ratio (RR)=0.63 (95% CI 0.54 to 0.73), p<0.00001). The overall quality of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) criteria was found to be moderate. In subgroup analyses, high dose compared with low dose of the same probiotic demonstrated a positive protective effect (RR 0.54 (95% CI 0.38 to 0.76), p<0.01), and only certain species, mainly of the lactobacillus and bifidobacteria genera, were found to be effective. Studies with a low baseline AAD risk did not show any difference in risk but studies with moderate or high baseline AAD risk demonstrated a significant risk reduction.

Conclusions Probiotics are effective for preventing AAD. Secondary analyses of higher dosages and certain species have shown increased effectiveness. Our results may not be applicable in clinical scenarios of lower baseline AAD risk.

  • bacteriology
  • gastrointestinal infections
  • gastroenterology
  • preventive medicine
  • adult gastroenterology
  • nutrition & dietetics

Data availability statement

Raw data used and analysed during the current study are available from the corresponding author on reasonable request.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

Raw data used and analysed during the current study are available from the corresponding author on reasonable request.

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  • Twitter @runningdoc14, @LevettKate

  • Contributors Study concept and design: CG, CH, KL. Acquisition of data: CG, GK, KL. Analysis and interpretation of data: CG, GK, KL. Drafting of the manuscript: CG, KL. Critical revision of the manuscript for important intellectual content: CG, GK, EG, KL. Statistical analysis: CG, EG, KL. Study supervision: KL.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.