Two recent studies published in the New England Journal of Medicine called into question the use of specific probiotic formulations in children with gastroenteritis. You can check out the podcast interview with David Schnadower, the principal investigator of the US study right here.

Check the NEJM study from Schnadower et al. here

What did we know about probiotics in gastroenteritis before this study?

Upwards of 1.7 million children are diagnosed with acute gastroenteritis every year. A meta-analysis of fifteen randomized trialsshowed a benefit in duration of diarrhea when probiotics were used.

Because of this evidence, probiotics have been included as part of some care pathways for gastroenteritis and as targets for quality improvement initiatives. The use (and cost) of probiotics has been on the rise in general in the last decade.

What did they do in these studies?

Two parallel randomized control trials were recently published in the New England Journal of Medicineexamining probiotics in the treatment of acute gastroenteritis. 

The US study, performed by David Schnadower and the Pediatric Emergency Care Applied Research Network (PECARN), enrolled 971 children with acute gastroenteritis. They were aged 3 months to 4 years and had similar demographic and disease severity characteristics at enrollment. They were randomized to receive either placebo or Lactobacillus rhamnosus GG for five days. There was no significant difference in the primary outcome of moderate-severe symptoms after starting the placebo or probiotic. There was also no significant difference in frequency or duration of vomiting and diarrhea, school absenteeism or unscheduled healthcare visits for gastroenteritis symptoms. In the figure below, the analysis by subgroup demonstrates no significant difference in outcomes with age, duration, antibiotics or type of infection isolated.

The second studywas performed by a similar group in Canada, led by Stephen Freedman. They examined 886 children with acute gastroenteritis, randomizing them to placebo or a combined probiotic (Lactobacillus rhamonosus-Lactobacillus helveticus). The also showed no difference in similar outcomes as the Schnadower study. 

This figure demonstrates the similarities in outcomes in the subgroups of the Schnadower study.

What does this change?

Prior to this pair of studies, the use of probiotics was routinely recommended by many physicians for the management of acute gastroenteritis on the basis of prior evidence. With the results of these two trials, we can now say that probiotics do not reduce the number of episodes of vomiting or diarrhea, or reduce school absenteeism in children with acute gastroenteritis.

The Bottom Line

These studies technically only apply to Lactobacillus rhamnosus GG and the combined probiotic Lactobacillus rhamonosus-Lactobacillus helveticus.

These two probiotics do not reduce the severity of gastroenteritis in children 

Providers should not routinely recommend them to children with gastroenteritis


Freedman et al. Multicenter Trial of a Combination Probiotic for Children with Gastroenteritis. N Engl J Med 2018; 379:2015-2026. DOI: 10.1056/NEJMoa1802597.

Parker et al. Rapid adoption of Lactobacillus rhamnosus GG for acute gastroenteritis. Pediatrics, 2013.

Schnadower et al. Lactobacillus rhamnosus GG versus Placebo for Acute Gastroenteritis in Children. NEJM 2018; 379:2002-2014. DOI: 10.1056/NEJMoa1802598.

Szajewska et al. Meta-analysis: Lactobacillus GG for treating acute gastroenteritis in children–updated analysis of randomised controlled trials. Aliment Pharmacol Ther. 2013 Sep;38(5):467-76. doi: 10.1111/apt.12403. Epub 2013 Jul 10.