Lactobacillus rhamnosus GG
Lacticaseibacillus rhamnosus GG (ATCC 53103)
LGG is the most-studied probiotic strain in the world, with strong evidence for shortening infectious diarrhea in children and preventing antibiotic-associated diarrhea, plus moderate evidence in eczema prevention and travelers' diarrhea.
At a Glance
- Best known for
- Shortens acute infectious diarrhea in children by about a day, Reduces risk of antibiotic-associated diarrhea in children and adults, May reduce eczema risk in high-risk infants when given to mothers and babies
- Evidence
- Strong
- Typical dose
- 10–20 billion CFU daily for 5–7 days
- Type
- Probiotic
What is Lactobacillus rhamnosus GG?
Lactobacillus rhamnosus GG (now formally Lacticaseibacillus rhamnosus GG) was isolated from a healthy human gut in 1985 by Sherwood Gorbach and Barry Goldin, whose initials give it the 'GG'. It was selected for its ability to survive stomach acid and bile and to adhere strongly to the intestinal lining, and it has since appeared in more than 1,000 scientific publications and hundreds of clinical trials, making it the single best-characterized probiotic strain. It is sold worldwide in capsules, drops, dairy products and infant formulas, and it is the strain behind many of the general claims made for 'probiotics'. Because probiotic effects are strain-specific, LGG's evidence does not automatically transfer to other L. rhamnosus strains.
Known Health Benefits
How It Works
LGG's surface pili (SpaCBA) bind intestinal mucus, letting it persist in the gut for days to weeks rather than passing through. It competes with pathogens for adhesion sites and nutrients, produces lactic acid that lowers local pH, and secretes proteins (p40, p75) that activate epidermal growth factor receptor signaling in gut cells, reducing cell death and strengthening tight junctions between epithelial cells. It enhances mucin and secretory IgA production, and modulates immune responses toward tolerance by stimulating regulatory T cells and IL-10 while dampening inflammatory cytokines, the proposed mechanism in eczema prevention. In acute diarrhea, these effects shorten the time the gut lining takes to recover and reduce fluid loss. In the upper airways, immune priming via gut-associated lymphoid tissue may explain modest reductions in respiratory infections.
What Research Says
LGG has a large trial base of generally good quality. A 2020 Cochrane review of probiotics for acute infectious diarrhea (82 trials, over 12,000 participants) found that LGG and other probiotics may shorten diarrhea, though newer large trials in North America showed no benefit in emergency-department settings, which tempered earlier enthusiasm; European pediatric guidelines still recommend LGG at 10 billion CFU or more. A 2015 meta-analysis of 12 RCTs (1,499 patients) found LGG reduced antibiotic-associated diarrhea risk from 22.4% to 12.3%, and a 2019 Cochrane review supports probiotics for this use in children. For eczema, meta-analyses of prenatal and postnatal LGG show roughly a 20–40% relative reduction in infant eczema in high-risk families, though individual trials conflict. LGG reduces travelers' diarrhea modestly and respiratory infections in daycare children in Finnish trials. Evidence for IBS, weight and anxiety is weak. Safety data from tens of thousands of participants are reassuring outside of critically ill or severely immunocompromised patients.
Active Compounds
Live Lacticaseibacillus rhamnosus GG cells; SpaCBA pili (mucus-binding), exopolysaccharides, p40 and p75 secreted proteins, lactic acid
Forms & Bioavailability
LGG survives stomach acid and bile well, which is why it was chosen; roughly 10–30% of ingested cells reach the colon alive, and the strain can be detected in stool for 1–2 weeks after stopping. It does not permanently colonize most adults, so benefits require continued intake. Refrigerated or well-formulated shelf-stable products maintain potency; CFU counts should be guaranteed through expiry rather than at manufacture. Taking it with a meal buffers stomach acid and improves survival.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| Acute diarrhea in children | 10–20 billion CFU daily for 5–7 days |
| Antibiotic-associated diarrhea prevention | 10–20 billion CFU daily, throughout antibiotic course and 1 week after |
| Eczema prevention (high-risk infants) | 10 billion CFU daily to mother from 36 weeks and to infant for 6 months |
| General gut support (adults) | 5–10 billion CFU daily |
| Travelers' diarrhea | 2–10 billion CFU daily, starting 2 days before travel |
Always consult a healthcare provider for personalized dosing.
Natural Food Sources
- Fermented dairy products labeled with LGG (certain yogurts, kefir and cultured milks)
- Infant formulas supplemented with LGG
- Not naturally present in foods; LGG is an added culture
Potential Side Effects
Mild bloating or gas in the first days; rare cases of bacteremia in critically ill, immunocompromised or central-line patients and premature infants
Who Should Avoid It
- Severe immunosuppression (chemotherapy, transplant, advanced HIV) without medical advice
- Central venous catheter in place
- Critically ill or ICU patients, including those with severe acute pancreatitis
- Premature infants (use only specific NICU-approved products under supervision)
- Short bowel syndrome (case reports of bacteremia)
Pregnancy & Lactation
LGG has been given to pregnant women from 36 weeks of gestation and to breastfeeding mothers in multiple randomized trials, including the Finnish eczema-prevention studies, with no safety concerns identified. It is considered one of the safest probiotics in pregnancy. Infants have received LGG in formula and drops in large trials with good tolerability.
Known Drug Interactions
Antibiotics kill LGG — separate doses by at least 2 hours; antifungals do not affect it; immunosuppressants increase the (small) risk of infection from any live probiotic
Evidence Classification
Supported by randomized controlled trials (RCTs), systematic reviews, or meta-analyses published in peer-reviewed journals.
Frequently Asked Questions
Why do some recent studies say LGG does not work for diarrhea?
Two large, well-run 2018 trials in US and Canadian emergency departments found LGG (and an LGG-containing product) did not shorten diarrhea in children compared with placebo. Earlier European and Asian trials, where diarrhea was often more severe and started later, showed benefit. The honest reading is that LGG helps modestly in some settings, especially when started early with a dose of 10 billion CFU or more, and the effect is smaller than once believed.
Does LGG prevent eczema in babies?
Several trials in which mothers took LGG in late pregnancy and infants took it for 6 months found about a one-third reduction in eczema in high-risk families (where a parent or sibling has allergies), though a UK trial found no effect. International allergy guidelines call the evidence suggestive but not conclusive. It is reasonable to try in high-risk families, with low risk of harm.
Is LGG the same as other Lactobacillus rhamnosus products?
No. Probiotic effects are strain-specific. The research supports the GG strain (ATCC 53103) specifically; other L. rhamnosus strains such as HN001 or GR-1 have their own, different evidence. Check that the label says 'GG' or 'ATCC 53103'.
Can LGG cause an infection?
Very rarely. Cases of LGG bloodstream infection have occurred almost exclusively in patients who were critically ill, severely immunocompromised, premature, or had central venous catheters, and investigation sometimes traced them to probiotic powder contaminating catheter lines. For healthy people, including children and pregnant women, the risk is negligible.
References
- Probiotics for treating acute infectious diarrhoea. Collinson S, Deans A, Padua-Zamora A, et al.. Cochrane Database Syst Rev (2020)View study
- Systematic review with meta-analysis: Lactobacillus rhamnosus GG in the prevention of antibiotic-associated diarrhoea in children and adults. Szajewska H, Kołodziej M. Aliment Pharmacol Ther (2015)
- Thirty Years of Lactobacillus rhamnosus GG: A Review. Capurso L. J Clin Gastroenterol (2019)
- Probiotics: What You Need To Know. National Center for Complementary and Integrative Health. NCCIH (2019)View study
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.