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.
Outcome
Evidence
Effect
Studies
Infant colic crying timeMeta-analyses show ~43-46 min/day less crying, strongest in breastfed; large BMJ trial (Sung 2014) was negative.
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.
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?