There is no evidence that probiotics are effective in treating acute infectious diarrhea, state the authors of this Cochrane review update. Previous editions of the review had suggested they were; but a review update of the evidence, which included new trials, has overturned the review's previous findings.
A previous version of the Cochrane review, consisting of 63 trials, seemed to show probiotics were effective. In this update, the addition of new trials, including two large well-conducted trials; the finding of substantive publication bias; and the use of GRADE led to a change in the authors' assessment of effectiveness.
Authors from LSTM, the Philippines, and New Zealand undertook this extensive update of this Cochrane Review (link is external) looking at the effectiveness of treating acute infectious diarrhea with probiotics.
Acute infectious diarrhea is a major global disease that particularly affects children in low- and middle-income countries. Acute diarrhea usually improves within a few days. However, in severe acute diarrhea, the loss of water and salts from the body may be substantial, causing dehydration and even death.
The review authors examined evidence from 82 studies with a total of 12,127 participants, and overall found no difference between taking a probiotic versus placebo or no additional treatment in shortening the duration of diarrhea.
Probiotics made no difference to the number of people with diarrhoea lasting 48 hours or more and the evidence for shortening the duration of diarrhoea was very weak. We hope that our findings will discourage the use of probiotics for acute infectious diarrhoea. This will have beneficial effects in reducing costs and also not detracting from important interventions such as maintaining or improving hydration".
Stephen Allen, Study Senior Author and Professor, Liverpool School of Tropical Medicine
Collinson, S., et al. (2020) Probiotics for treating acute infectious diarrhoea. Cochrane Database of Systematic Reviews. doi.org/10.1002/14651858.CD003048.pub4.