Lactobacillus reuteri: Evidence Profile for Infant Colic, Oral Health and Beyond
What trials and reviews found for Limosilactobacillus reuteri DSM 17938 in infant colic, children's diarrhea, preterm infants and oral health, including the large trial that found no benefit.
Content last updated . This page has not been medically reviewed.
What is Lactobacillus reuteri (Limosilactobacillus reuteri) good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Reduced crying time in breastfed infants with colic (DSM 17938 only)
Preliminary or mixedIn a pooled analysis of four double-blind trials, babies with colic who were given L. reuteri DSM 17938 had less crying and fussing than those given placebo, mainly breastfed babies.
Supplements: Promising but limited and mixed: pooled trials favour breastfed infants, a large community trial found no benefit, and the NHS says probiotic supplements are not recommended for colic.
Formula-fed infants with colic
Not enough evidenceFor formula-fed babies the pooled analysis found no significant effect and said the data were too few to conclude.
Supplements: Insufficient evidence in formula-fed infants.
Large community colic trial with no benefit
Preliminary or mixedA trial of 167 breastfed and formula-fed infants under 3 months in Melbourne found no benefit from DSM 17938 and did not support a general recommendation.
Supplements: Mixed evidence: the largest community trial was negative.
Preventing colic
Not enough evidenceA Cochrane review of six trials found no clear evidence that probiotics given to newborns prevent colic (low certainty). Only two of the six tested an L. reuteri strain.
Supplements: Insufficient evidence for prevention.
Shorter acute diarrhoea in children
Preliminary or mixedThe AGA found L. reuteri may shorten childhood diarrhoea by about 24 hours (low certainty), but the trials it cites were not done in North America and it suggests against probiotics for this use in North America. ESPGHAN (2014) gave only a weak recommendation on very low-quality evidence.
Supplements: Mixed; guideline positions differ by region.
Necrotizing enterocolitis in preterm infants (hospital use only)
Clinically supportedThe AGA found high-certainty evidence that DSM 17938 or ATCC 55730 lowered severe necrotizing enterocolitis in preterm infants. The FDA (2023) warns that preterm infants given probiotics risk invasive, potentially fatal infection, so this is a decision for the hospital team only.
Supplements: Supported in trials for a defined hospital population; not a general or home use.
Gum disease (chronic periodontitis) as an add-on to dental cleaning
Preliminary or mixedA 30-patient trial of L. reuteri lozenges found more pocket-depth reduction when added to dental cleaning; a 2024 review of 11 studies (369 people) said the evidence is limited.
Supplements: Promising but limited.
Preventing antibiotic-associated diarrhoea in children
Not enough evidenceA 2022 review said this strain does not seem to prevent antibiotic-associated diarrhoea in children.
Supplements: No good evidence of benefit for this use.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Health goals (1)
- Digestive SupportPreliminary or mixed
L. reuteri DSM 17938 has been studied mainly for colic in breastfed babies, with mixed results; the NHS does not recommend probiotics for colic. Results do not transfer to other strains.
Body systems (2)
- Digestive SystemPreliminary or mixed
Studied for infant colic and childhood diarrhoea with mixed results, for one strain (DSM 17938) only.
- Gut HealthPreliminary or mixed
Studied for infant colic and childhood diarrhoea with mixed results, for one strain (DSM 17938) only.
Body parts (1)
- GutPreliminary or mixed
The trials concern gut symptoms in infants (colic, diarrhoea) and necrotizing enterocolitis in preterm babies; evidence is strain- and condition-specific.
Functional actions (1)
- Digestive SupportPreliminary or mixed
L. reuteri DSM 17938 has been studied mainly for colic in breastfed babies, with mixed results; the NHS does not recommend probiotics for colic.
Conditions & symptoms (5)
- Infantile ColicPreliminary or mixed
DSM 17938 gave less crying in breastfed babies in pooled trials; a large community trial found no benefit and the NHS does not recommend probiotics for colic. Not shown for formula-fed babies.
- Acute GastroenteritisPreliminary or mixed
The AGA found this strain may shorten children's diarrhoea by about 24 hours (low certainty) but suggests against probiotics for it in North America; ESPGHAN 2014 gave a weak recommendation on very low-quality evidence.
- BacteremiaDocumented risk
Preterm infants given probiotic products risk invasive, potentially fatal infection (FDA 2023); NCCIH says risk is greater in severe illness or weakened immunity.
- Necrotizing EnterocolitisClinically supported
The AGA found high-certainty evidence that DSM 17938 or ATCC 55730 lowered severe disease in preterm infants. The FDA warns of invasive, potentially fatal infection in preterm infants, so this is a hospital-team decision only.
- Chronic PeriodontitisPreliminary or mixed
A 30-patient trial of lozenges added to dental cleaning found more pocket-depth reduction; a 2024 review said evidence is limited.
Documented risks and interactions (2)
- Infection risk in preterm, severely ill and immunocompromised people. The FDA warns that preterm infants given probiotic products risk invasive, potentially fatal infection. NCCIH says the risk of harm is greater in people with severe illness or a weakened immune system.
- Product quality and strain labelling. The NHS notes probiotics are generally classed as food, so we cannot always be sure a product contains what the label says. The strain code on a product should match the one tested in trials.
If your baby is crying a lot, start here
Colic is a baby who cries a lot with no obvious cause but is otherwise healthy. The NHS (UK) says it usually settles by 3 to 4 months. [1] It lists a weak or high-pitched cry, or a cry that does not sound like the baby's normal cry, as a reason for immediate emergency care (in the US, call 911). [1] It also advises calling a health professional if you are worried, if the baby is not growing as expected, or if you are struggling to cope. [1] The NHS says probiotic supplements for colic are not recommended and that there is no evidence they help. [1] Some studies disagree, as below. Talk to your baby's clinician before giving any probiotic to an infant, and see probiotics for infants and babies.The short answer
Limosilactobacillus reuteri (formerly Lactobacillus reuteri) DSM 17938 is the strain behind most colic trials. Early trials in breastfed infants were positive, a large community trial was not, and reviews that pool them lean positive only for breastfed babies, with limited certainty. None of this applies to other L. reuteri strains or to other probiotics. [2]Evidence labels: promising but limited, mixed, insufficient evidence, no good evidence of benefit. Amounts are study amounts, not advice.
Infant colic: trial by trial
| Study | Who and what was tested | What it found |
|---|---|---|
| Savino 2010 (Italy) | 50 exclusively breastfed infants; DSM 17938, 10^8 CFU a day, 21 days | Crying was shorter on day 21 than with placebo. [3] |
| Chau 2015 (Canada) | 52 breastfed infants; DSM 17938, 10^8 CFU, 21 days | Crying and fussing time was shorter than with placebo. [4] |
| Sung 2014 (Australia) | 167 breastfed and formula-fed infants under 3 months from the community; 10^8 CFU a day for 1 month | Babies on the probiotic cried or fussed about 49 minutes more than placebo at 1 month; the authors did not support a general recommendation. [5] |
| Pooled individual data, 2018 | 4 trials, 345 infants | Success was almost twice as likely overall; effect was clear in breastfed infants and insignificant in formula-fed infants. [6] |
| Review of breastfed infants, 2021 | 10 trials (ATCC 55730 and DSM 17938) | Crying time fell, but confidence was very low for crying time and low for treatment success. [7] |
| Meta-analysis, 2026 | 11 trials, 555 infants, DSM 17938 | Treatment response was higher than placebo (odds ratio 6.98), with a call for better trials. [8] |
| Cochrane, 2019 (prevention) | Newborn babies given probiotics to prevent colic (6 trials; only 2 tested L. reuteri DSM) | No clear difference in new cases of colic (low certainty). [9] |
Label: mixed. For exclusively breastfed infants the pooled evidence is promising but limited; for formula-fed infants, insufficient. [6] Colic trials rely on parents' diaries, and the biggest community trial found no benefit, so results may depend on who is enrolled. [5]
Beyond colic
| Use | What the sources found | Label |
|---|---|---|
| Children's acute diarrhea | The AGA found L. reuteri may shorten diarrhea by about 24 hours (low CoE), but noted that none of the trials in the strain-specific reviews it cites were done in North America, and it suggests against probiotics for this in North America. [10][11] ESPGHAN (2014) gave only a weak recommendation on very low-quality evidence. [12] | Mixed |
| Preventing necrotizing enterocolitis in preterm infants | The AGA found high-certainty evidence that DSM 17938 or ATCC 55730 lowered severe disease. [10] The FDA (US, 2023) warns that preterm infants given probiotics risk invasive, potentially fatal disease. [13] | Hospital decision only |
| Gum disease (periodontitis), as an add-on to dental cleaning | A 30-patient trial of lozenges found more pocket-depth reduction. [14] A 2024 review of 11 studies (369 people) said evidence is limited. [15] | Promising but limited |
| Antibiotic-associated diarrhea in children | A 2022 review said this strain does not seem to prevent it. [16] | Insufficient evidence |
Frequently asked questions
Does L. reuteri help infant colic?
Results are mixed. Several trials and pooled analyses favor DSM 17938 in breastfed babies, while a large community trial did not, and the NHS does not recommend probiotic supplements for colic. [6][5][1]
Does it work for formula-fed babies?
The pooled analysis found no significant effect in formula-fed infants and said data were insufficient. [6]
Is Lactobacillus reuteri the same as Limosilactobacillus reuteri?
Yes. It was renamed after the 2020 reclassification of the genus. [19][16]
Can I give it to a premature baby?
Only the neonatal team should decide. The FDA warns of potentially fatal infections in preterm infants. [13]
Is it safe for adults?
This page found no strain-specific adult safety review. NCCIH says harm is more likely in people who are very ill or immunocompromised. [17]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
- Infants. NCCIH (US) reports no harmful effects in a review of 4 colic studies (345 participants) of this strain. [17] A 2026 meta-analysis found no safety concerns, but only in the trials included. [8]
- Immunocompromised people and serious illness. NCCIH says risk is greater in severe illness or weakened immunity. [17] See probiotic safety.
- Medicines, pregnancy, kidney or liver conditions, surgery. Not described for this strain in the sources we read (Proper evidence not found). Ask a clinician or pharmacist; see how medicine interactions work.
- Products. The NHS cautions that we cannot always be sure a probiotic contains what the label says. [18] Compare the strain code on a product with the one in the trial. See probiotic strains and labels.
References
- NHS (UK). Colic. Read 2026-10-22.
- McFarland LV, Evans CT, Goldstein EJC. Strain-Specificity and Disease-Specificity of Probiotic Efficacy: A Systematic Review and Meta-Analysis. Front Med 2018. PMID 29868585. Read 2026-10-22.
- Savino F et al. Pediatrics 2010. Lactobacillus reuteri DSM 17938 in infantile colic: a randomized, double-blind, placebo-controlled trial. PMID 20713478. Read 2026-10-22.
- Chau K et al. J Pediatr 2015. Probiotics for infantile colic: a randomized, double-blind, placebo-controlled trial investigating Lactobacillus reuteri DSM 17938. PMID 25444531. Read 2026-10-22.
- Sung V et al. BMJ 2014. Treating infant colic with the probiotic Lactobacillus reuteri: double blind, placebo controlled randomised trial. PMID 24690625. Read 2026-10-22.
- Sung V et al. Pediatrics 2018. Lactobacillus reuteri to Treat Infant Colic: A Meta-analysis. PMID 29279326. Read 2026-10-22.
- Zermiani APDRB et al. Complement Ther Med 2021. Evidence of Lactobacillus reuteri to reduce colic in breastfed babies: Systematic review and meta-analysis. PMID 34627993. Read 2026-10-22.
- Bianchi M et al. Nutrition 2026. Efficacy of Lactobacillus reuteri DSM 17938 in preterm newborns and infants with colic: a systematic review and meta-analysis of randomized controlled trials. PMID 42485904. Read 2026-10-22.
- Ong TG et al. Cochrane Database Syst Rev 2019. Probiotics to prevent infantile colic. PMID 30865287. Read 2026-10-22.
- Preidis GA et al. AGA Technical Review on the Role of Probiotics in the Management of Gastrointestinal Disorders. Gastroenterology 2020 (full text read via PMC8018518). PMID 32531292. Read 2026-10-22.
- Su GL et al. AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders. Gastroenterology 2020 (guideline text read from a hosted copy of the published PDF). PMID 32531291. Read 2026-10-23.
- Szajewska H et al. J Pediatr Gastroenterol Nutr 2014. Use of probiotics for management of acute gastroenteritis: a position paper by the ESPGHAN Working Group for Probiotics and Prebiotics. PMID 24614141. Read 2026-10-22.
- FDA (US Food and Drug Administration). Risk of Invasive Disease in Preterm Infants Given Probiotics Formulated to Contain Live Bacteria or Yeast (safety communication, 2023). Read 2026-10-23.
- Teughels W et al. J Clin Periodontol 2013. Clinical and microbiological effects of Lactobacillus reuteri probiotics in the treatment of chronic periodontitis: a randomized placebo-controlled study. PMID 24164569. Read 2026-10-22.
- Ram J et al. Eur Rev Med Pharmacol Sci 2024. Clinical effects of Lactobacillus reuteri probiotic in chronic periodontitis - a systematic review. PMID 38497853. Read 2026-10-22.
- Dargenio VN et al. Benef Microbes 2022. Use of Limosilactobacillus reuteri DSM 17938 in paediatric gastrointestinal disorders: an updated review. PMID 35212258. Read 2026-10-22.
- NCCIH (US National Center for Complementary and Integrative Health). Probiotics: Usefulness and Safety. Read 2026-10-22.
- NHS (UK). Probiotics. Page last reviewed 24 November 2022. Read 2026-10-22.
- Zheng J et al. A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae. PMID 32293557. Read 2026-10-22.