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Lactobacillus reuteri DSM 17938

Limosilactobacillus reuteri DSM 17938 (Protectis)

The best-studied probiotic for infant colic and pediatric gut complaints

Moderate evidence 🦠Probiotics🛡️Gut & Immune

✚ Updated · How we grade evidence

Evidence tier
Moderate
Research weight
Citations
8 verified / 8
Classification
Probiotics
❝
What the evidence says. Several controlled trials; effects real but modest or context-dependent.

What is Lactobacillus reuteri DSM 17938?

Lactobacillus reuteri DSM 17938 (Limosilactobacillus reuteri DSM 17938 (Protectis)) is a probiotic strain used for reduces infant colic crying time by ~40-50 min/day at 2-3 weeks, strongest in breastfed infants. NutriDex grades the human evidence as Moderate. Limosilactobacillus reuteri DSM 17938 (Protectis, the daughter strain of ATCC 55730) is among the most rigorously trialed probiotics in pediatrics. Meta-analyses of RCTs show it meaningfully reduces daily crying in colicky infants — roughly 40-50 minutes/day at 2-3 weeks — with the most consistent benefit in exclusively/predominantly breastfed infants; a large community-based BMJ trial (Sung 2014) was negative, so the colic evidence is best graded moderate/mixed and population-dependent. It also modestly shortens acute infectious diarrhea (about 0.9 day) and reduces functional abdominal pain frequency/intensity in children. Evidence for preventing antibiotic-associated diarrhea is weak/inconclusive.

Purported Benefits

✓Reduces infant colic crying time by ~40-50 min/day at 2-3 weeks, strongest in breastfed infants
✓Shortens duration of acute infectious gastroenteritis/diarrhea in children by ~0.9 day and shortens hospital stay
✓Reduces frequency and intensity of functional (recurrent) abdominal pain in children, increasing pain-free days
✓Prophylactic use in the first 3 months lowers onset of functional GI disorders (colic, regurgitation, constipation) per Indrio 2014
✓Increases stool frequency in infants and may ease functional constipation

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Infant colic crying timeMeta-analyses show ~43-46 min/day less crying, strongest in breastfed; large BMJ trial (Sung 2014) was negative. Mixed ↑ benefit · moderate 3
Acute infectious diarrhea duration (children)Meta-analyses show ~0.9-day shorter diarrhea and shorter hospital stay; modest effect. Moderate ↑ benefit · small 2
Functional abdominal pain (children)One RCT (Weizman, n=101) reduced pain frequency/intensity over 4 weeks. Preliminary ↑ benefit · moderate 1
Antibiotic-associated diarrhea prevention (children)2025 systematic review (2 RCTs) found no significant effect; low certainty. Preliminary — no effect · negligible 1

Dosing & Compounds

Typical Dose
1x10^8 CFU/day (5 drops of oil suspension) once daily; in colic trials given ~30 min before/with a feed for 21-28 days; pediatric FAP trials used 1-2x10^8 CFU/day for 4-12 weeks.
Active Compounds
Limosilactobacillus reuteri DSM 17938 (renamed from Lactobacillus reuteri)Parent strain L. reuteri ATCC 55730BioGaia Protectis drops / chewable tabletsGerber Soothe (US)Oil-suspension drops dosed at 5 drops (~1x10^8 CFU)

Safety & Cautions

Very well tolerated in infants and children; trials report no effect on growth and no serious strain-attributable adverse events. As with any live probiotic, use caution in critically ill, premature/short-gut, central-venous-catheter, or immunocompromised patients given the theoretical risk of bacteremia/sepsis; discuss with a clinician in those settings. Educational only — always check with your doctor or pharmacist before combining Lactobacillus reuteri DSM 17938 with any medicine.

Key Studies

systematic review Szajewska 2025 ✓ PubMed
Systematic review for preventing antibiotic-associated diarrhea in children found no significant effect (2 RCTs, n=901; RR 0.85, 95% CI 0.26-2.77; low certainty).
meta-analysis Sung 2018 (Harb/Sung et al., PLOS One 2015) ✓ Full text
Meta-analysis of 6 RCTs (n=423) found L. reuteri DSM 17938 cut crying time vs placebo by WMD -42.9 min/day at 2 wk and -45.8 min/day at 3 wk.
network meta-analysis Schreck Bird 2017 ✓ Full text
Systematic review with network meta-analysis identified L. reuteri DSM 17938 as the most evidence-based intervention for reducing crying duration in infantile colic.
meta-analysis Patro-Gołąb & Szajewska 2019 ✓ Full text
Updated meta-analysis (4 RCTs, n=347) showed DSM 17938 reduced acute gastroenteritis diarrhea duration by MD -0.87 days (95% CI -1.43 to -0.31) and shortened hospitalization.
meta-analysis Szajewska 2016 ✓ PubMed
Systematic review with meta-analysis concluded DSM 17938 reduces duration of acute diarrhea in children (3 RCTs, n=256, MD -24.8 h) and raises cure rate.
randomized controlled trial Weizman 2016 ✓ PubMed
RCT in 101 children (Rome III functional abdominal pain) found DSM 17938 significantly reduced pain frequency (1.9 vs 3.6 episodes/wk, P<.02) and intensity vs placebo over 4 weeks.
randomized controlled trial Sung 2014 (BMJ) ✓ PubMed
Double-blind RCT in 167 community infants (breast- and formula-fed) found L. reuteri DSM 17938 did NOT reduce crying/fussing, tempering colic claims in unselected populations.
randomized controlled trial Indrio 2014 (JAMA Pediatr) ✓ PubMed
RCT prophylaxis in first 3 months reduced crying at 90 days (38 vs 71 min/day), regurgitation episodes, and increased daily evacuations, lowering functional GI disorder onset.
8 sources cited · 8 verified Search all studies on PubMed ↗

Common questions about Lactobacillus reuteri DSM 17938

What is Lactobacillus reuteri DSM 17938 used for?

Lactobacillus reuteri DSM 17938 is most often taken for Reduces infant colic crying time by ~40-50 min/day at 2-3 weeks, strongest in breastfed infants, Shortens duration of acute infectious gastroenteritis/diarrhea in children by ~0.9 day and shortens hospital stay, Reduces frequency and intensity of functional (recurrent) abdominal pain in children, increasing pain-free days, Prophylactic use in the first 3 months lowers onset of functional GI disorders (colic, regurgitation, constipation) per Indrio 2014. The best-studied probiotic for infant colic and pediatric gut complaints

Does Lactobacillus reuteri DSM 17938 work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. Limosilactobacillus reuteri DSM 17938 (Protectis, the daughter strain of ATCC 55730) is among the most rigorously trialed probiotics in pediatrics. Meta-analyses of RCTs show it meaningfully reduces daily crying in colicky infants — roughly 40-50 minutes/day at 2-3 weeks — with the most consistent benefit in exclusively/predominantly breastfed infants; a large community-based BMJ trial (Sung 2014) was negative, so the colic evidence is best graded moderate/mixed and population-dependent. It also modestly shortens acute infectious diarrhea (about 0.9 day) and reduces functional abdominal pain frequency/intensity in children. Evidence for preventing antibiotic-associated diarrhea is weak/inconclusive.

What is the typical dose of Lactobacillus reuteri DSM 17938?

1x10^8 CFU/day (5 drops of oil suspension) once daily; in colic trials given ~30 min before/with a feed for 21-28 days; pediatric FAP trials used 1-2x10^8 CFU/day for 4-12 weeks.

Is Lactobacillus reuteri DSM 17938 safe? Any cautions or side effects?

Very well tolerated in infants and children; trials report no effect on growth and no serious strain-attributable adverse events. As with any live probiotic, use caution in critically ill, premature/short-gut, central-venous-catheter, or immunocompromised patients given the theoretical risk of bacteremia/sepsis; discuss with a clinician in those settings.

How many studies support Lactobacillus reuteri DSM 17938?

NutriDex cites 8 sources for Lactobacillus reuteri DSM 17938, graded "Moderate".

Cite this page
APA

Peh, D. (2026). Lactobacillus reuteri DSM 17938 (Limosilactobacillus reuteri DSM 17938 (Protectis)): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/l-reuteri-dsm17938

BibTeX
@misc{nutridex_l_reuteri_dsm17938,
  author       = {Peh, Daryl},
  title        = {Lactobacillus reuteri DSM 17938 (Limosilactobacillus reuteri DSM 17938 (Protectis)): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/l-reuteri-dsm17938},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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