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Lgg6.0
L. rhamnosus GG Research
Mostly mechanism / observational
49 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most L. rhamnosus GG studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 1999–2026 with a typical study size of 202 participants.
Based on 49 studies · 10 meta-analyses · 12 RCTs · 11,547 total participants
Confidence
High confidence
By outcome
Acute gastroenteritis & diarrhoea
Mostly mechanism / observational7 studies
Eczema & atopic disease
Mostly mechanism / observational7 studies
IBS & functional abdominal painRoughly halves the risk of diarrhea while taking antibiotics (strongest in children); little benefit for everyday digestion or for treating an existing stomach bug · Taken alongside the antibiotic course
Mostly mechanism / observational7 studies
Safety & bacteraemia risk
Mostly mechanism / observational7 studies
Antibiotic-associated diarrhoea
Mostly mechanism / observational5 studies
Preterm infants & NEC
Mostly mechanism / observational3 studies
Respiratory infections
Too few graded studies2 studies
Immune supportCut healthcare-associated diarrhea and symptomatic rotavirus in hospitalized children, but a 619-child trial found no reduction in respiratory infections · 2-4 weeks
Too few graded studies2 studies
Active research area
32 studies in the last 5 years · Latest meta-analysis: 2024
199920122026
1Meta-Analysisn=554 · large study2023
In plain English: The results from this review demonstrate that probiotics and synbiotics may be more efficacious than placebo in achieving treatment success, but the evidence is of low certainty.
Wallace C et al. · The Cochrane database of systematic reviews (2023)
Probiotics may achieve more treatment success when compared with placebo at the end of the treatment, with 50% success in the probiotic group versus 33% success in the placebo group (RR 1.57, 95% CI 1.05 to 2.36; 554 participants; 6 studies; I2 = 70%; low-certainty evidence).
It is not clear whether probiotics are more effective than placebo for complete resolution of pain, with 42% success in the probiotic group versus 27% success in the placebo group (RR 1.55, 95% CI 0.94 to 2.56; 460 participants; 6 studies; I2 = 70%; very low-certainty evidence).
Meta-analysis showed no difference in withdrawals due to adverse events between probiotics (1/275) and placebo (1/269) (RR 1.00, 95% CI 0.07 to 15.12).
In plain English: The definitive Cochrane review concludes probiotics, LGG included, probably make little or no difference to acute infectious diarrhea.
Collinson S et al. · Cochrane Database Syst Rev (2020)
In studies at low risk of bias, no difference in diarrhea lasting >=48 hours (RR 1.00, 0.91-1.09; moderate certainty)
Duration of diarrhea: mean difference -8.6 hours (95% CI -29.4 to +12.1); very low certainty
Subgroup analyses limited to LGG showed the same null result
In plain English: The implementation of RVI might affect the efficacy of LGG modifying local epidemiology and susceptibility of the target population to selected probiotics.
Lo Vecchio A et al. · Beneficial microbes (2022)
In RCT conducted before the introduction of RVI (n=2,932), LGG was effective in reducing the duration of diarrhoea compared with placebo or standard care (Median -23.80 h, 95% confidence interval (CI) -36.59 to -11.02]).
Only 2 RCTs (n=1,072) reported data of populations partially immunised against Rotavirus with an overall coverage of 44 and 67%, respectively.
In this population, LGG showed no efficacy in reducing the duration of diarrhoea (Median -5.34, 95%CI -12.9 to 2.22).
In plain English: LGG roughly halves antibiotic-associated diarrhea risk, but the effect is solid mainly in children and in H. pylori eradication regimens.
Szajewska H, Kołodziej M · Aliment Pharmacol Ther (2015)
Antibiotic-associated diarrhea fell from 22.4% to 12.3%; RR 0.49 (0.29-0.83) pooled across 11 RCTs, n=1,308 (12 RCTs, n=1,499 included overall)
Significant in children (5 RCTs, n=445, RR 0.48, moderate quality of evidence)
Not significant in adults overall (RR 0.48, 0.20-1.15)
In plain English: Co-supplementation of probiotics and inulin in CAD subjects for eight weeks had beneficial effects on depression, anxiety, and inflammatory biomarkers.
Moludi J et al. · Nutritional neuroscience (2022)
Co-supplementation of probiotics and inulin in CAD subjects for eight weeks had beneficial effects on depression, anxiety, and inflammatory biomarkers.
Adding inulin to probiotic supplements improved psychological outcomes and inflammatory biomarkers more effectively than two supplements separately.Trial registration: Iranian Registry of Clinical Trials identifier: IRCT20180712040438N4..
In plain English: This review sums up the expected benefits and effects for infants of pre-, pro-, syn-, and postbiotics added to infant formula regarding the microbiota, immunity, and allergies.
Lemoine A et al. · Nutrients (2023)
A new challenge for dairy industries is, therefore, to develop infant formulas inducing the maturation of immunity and the microbiota that can be observed in breastfed delivered vaginally, representing reference infants.
Streptococcus thermophilus, Lactobacillus reuteri DSM 17938, Bifidobacterium breve (BC50), Bifidobacterium lactis Bb12, Lactobacillus fermentum (CECT5716), and Lactobacillus rhamnosus GG (LGG) are some of the probiotics added to infant formula, according to a literature review of the past 10 years.
The most frequently used prebiotics in published clinical trials are fructo-oligosaccharides (FOSs), galacto-oligosaccharides (GOSs), and human milk oligosaccharides (HMOs).
In plain English: The ESPGHAN working group gives this strain a strong recommendation at moderate quality of evidence for preventing antibiotic-associated diarrhea in children.
Szajewska H et al. · J Pediatr Gastroenterol Nutr (2016)
ESPGHAN Working Group recommends Lactobacillus rhamnosus GG for preventing antibiotic-associated diarrhea in children: moderate quality of evidence, STRONG recommendation
Saccharomyces boulardii carries the same moderate-quality strong recommendation; other strains or combinations lacked sufficient evidence
Applies where risk factors exist — antibiotic class, treatment duration, age, need for hospitalization, comorbidities, or previous AAD episodes
In plain English: Further large and well-designed pediatric studies are needed to prove the efficacy and safety of different herbal extracts and prolonged use of studied products in infants and children with pain disorders of the gut-brain interaction.
Salvatore S et al. · Nutrients (2024)
Further large and well-designed pediatric studies are needed to prove the efficacy and safety of different herbal extracts and prolonged use of studied products in infants and children with pain disorders of the gut-brain interaction.
In plain English: However, further high-quality RCTs are needed to validate these findings and explore the mechanisms underlying the differential efficacy of probiotic strains.
Xiaohua L, Yiting D, Qin L, Yang Z, Shumao W, Li P, Yi P, Lingmei C, Wenge L, Maoxia L. · Frontiers in nutrition (2025)
Network meta-analyses were performed using random-effects models to calculate standardized mean differences (SMDs), odds ratios (ORs), and surface under the cumulative ranking curve (SUCRA) for different probiotics.
Lactobacillus GG (LGG) was identified as the most effective in reducing Scoring Atopic Dermatitis (SCORAD) scores (SMD = -4.24, 95% CI [-7.12, -1.36]; p < 0.05) and improving quality of life.
For IgE regulation, Lactobacillus acidophilus (LB) demonstrated the greatest efficacy ( p < 0.05).
In plain English: This review synthesizes evidence on circadian regulation, serotonergic and tryptophan metabolism, and microbiota-gut-brain interactions in SAD, and highlights mechanistic gaps for future studies.
Liu H, Kuang X, Zheng X. · Nutrients (2026)
Among candidate strains, Lacticaseibacillus rhamnosus GG (formerly Lactobacillus rhamnosus GG; LGG) has shown effects on intestinal barrier function, immune signaling, and host tryptophan metabolism in preclinical studies.
However, evidence derives largely from animal or non-seasonal depression models, and direct evidence in SAD is lacking.
Thus, LGG should be considered a mechanistically plausible candidate for future investigation rather than an established therapy.
In plain English: Instead, to avoid that these bacteria become a hazard, genetic stability should be periodically re-evaluated by whole genome sequencing (WGS) to ensure that only non-pathogenic variants are administered to vulnerable individuals.
Rossi F et al. · Nutrients (2022)
Virulence characterization of two strains that caused infections, a derivative of L. rhamnosus GG and L. paracasei LP10266, indicated that increased biofilm-forming capacity favors pathogenicity and it is determined by variable genetic traits.
This survey highlights that the strains of lactobacilli that cause infections are little characterized genetically.
Instead, to avoid that these bacteria become a hazard, genetic stability should be periodically re-evaluated by whole genome sequencing (WGS) to ensure that only non-pathogenic variants are administered to vulnerable individuals.
In plain English: A 619-child trial failed its primary endpoint: this strain did not significantly reduce the incidence of upper respiratory tract infections.
Damholt A et al. · Benef Microbes (2022)
Primary endpoint not met — no significant reduction in GP-confirmed upper respiratory tract infection incidence
None of the secondary efficacy endpoints were met either
619 children aged 2-6 in day care or primary school; 309 active vs 310 placebo over a 16-week intervention, single centre in Scotland
In plain English: Pooled older trials show roughly 0.85 day shorter diarrhea, but the effect is geographically inconsistent and contradicted by the single largest trial.
Szajewska H et al. · Aliment Pharmacol Ther (2019)
Pooled diarrhea duration: mean difference -0.85 day (-1.15 to -0.56) across 15 RCTs, n=3,820 (18 RCTs, 4,208 children included overall)
No effect on stool volume
Effect present at >=10^10 CFU/day, borderline below that