Lactobacillus Rhamnosus GG
Also known as: LGG, Lactobacillus rhamnosus GG, Culturelle strain, ATCC 53103
The most-studied probiotic strain in the world — diarrhea prevention, eczema risk reduction, and the gold-standard dossier.
In short
Lactobacillus rhamnosus GG (LGG) is the best-characterized probiotic strain in existence — isolated in 1983 and studied in more clinical trials than any other single microbe. Its evidence portfolio is exceptional: strong data for preventing antibiotic-associated diarrhea and infectious diarrhea in children, well-replicated findings that prenatal and early-infant administration reduces eczema risk in at-risk families, and supportive trials in allergy and immune contexts. It survives stomach acid and bile, adheres to the gut lining, and has a clean safety record including in preterm infants. Most LGG evidence is strain-specific — the letters 'GG' are the product.
- The world's most-studied probiotic strain (since 1983)
- Strong evidence: diarrhea prevention, pediatric eczema risk
- Survives GI transit; adheres to intestinal mucosa
- Safe even in preterm infants; strain-specific effects
What is Lactobacillus Rhamnosus GG?
In the probiotic world, one name carries more research weight than any other: Lactobacillus rhamnosus GG. The strain — isolated from a healthy human in 1983 by its namesake researchers Gorbach and Goldin — has accumulated a trial dossier no other microbe approaches, spanning antibiotic-associated diarrhea, childhood infectious diarrhea, eczema prevention, and immune development. It is the probiotic that taught the field its central lesson: effects are strain-specific, and the letters after the species name are what you are actually buying.
Where it comes from
Natural sources
- A specific strain of Lactobacillus rhamnosus (ATCC 53103), isolated in 1983
- Selected for acid/bile survival and intestinal adhesion
- Naturally occurring gut-resident species
How it's made
Capsules, powders, and drops; doses from 1–10 billion CFU/day depending on indication.
What it does in products
Benefits
Diarrhea prevention
strong evidenceMeta-analyses confirm LGG reduces antibiotic-associated and infectious diarrhea risk in children and adults — among the strongest single-strain evidence in probiotics.
Eczema risk reduction in infants
strong evidenceTrials where pregnant mothers and newborns received LGG report significantly lower eczema incidence in at-risk families — a landmark prevention finding.
IBS and gut comfort
moderate evidenceSome trials show reduced IBS symptoms and improved regularity, particularly in children; adult IBS data are more mixed.
Side effects & safety
Safety considerations
- Studied in pregnancy (eczema-prevention protocols) with a good safety record; standard care for preterm infants in some NICUs.
- Antibiotics — separate dosing by 2+ hours
- Immunosuppressants — caution with any live microbe
- Not for: Severe immunocompromise
- Not for: Central venous catheters (generic probiotic precaution)
How it's used
In supplements
1–10 billion CFU/day; diarrhea protocols use 10 billion during and 1–2 weeks after antibiotics; eczema-prevention protocols used 10 billion in late pregnancy and infancy.
In skincare
Not a topical ingredient.
Regulatory status
- Sold as a dietary supplement; GRAS for specific food uses. No FDA-approved disease claims.
- GRAS (generally recognized as safe) for food use.
- Not applicable.
Popular products containing Lactobacillus Rhamnosus GG
- Culturelle Digestive Health (LGG) — The reference LGG productCulturelle · Supplement
- FlorastorKids / pediatric LGG drops — Infant formulationsVarious · Supplement
- Renew Life / multistrain with LGG — LGG-containing blendsRenew Life · Supplement
Product names and brands are shown for reference and belong to their respective owners.
Why the strain letters matter
Probiotic effects are strain-specific: L. rhamnosus GG's diarrhea and eczema data do not transfer to other L. rhamnosus strains or to the genus generally. The 'GG' designation identifies the exact organism in the trials — which is why serious probiotic recommendations name the strain, not the species.
The eczema-prevention protocol
In landmark trials, LGG given to pregnant women (2–4 weeks before delivery) and to infants for 6 months halved eczema incidence in high-risk families — effects that persisted in follow-up. This is among the most important probiotic findings in pediatrics and the reason LGG appears in prenatal and infant protocols worldwide.
Frequently asked questions
Is Culturelle the only LGG product?
No — many brands license or formulate with LGG (ATCC 53103), but Culturelle is the original reference product. Check labels for the strain designation.
Can I give LGG to my baby?
LGG has pediatric trial support including preterm infants, but discuss with your pediatrician — especially for infants under 3 months.
How does LGG compare to other probiotics?
It has the largest single-strain evidence base, particularly for diarrhea and infant eczema. Multi-strain products add diversity but dilute per-strain dosing.
The bottom line
Lactobacillus rhamnosus GG is the gold-standard probiotic — the strain whose diarrhea and eczema evidence defines what a well-studied probiotic can achieve.
References
- Lactobacillus GG: a review of clinical evidence. PubMed Central. https://pubmed.ncbi.nlm.nih.gov/30797500/
- LGG in eczema prevention: follow-up trials. Journal of Allergy and Clinical Immunology. https://pubmed.ncbi.nlm.nih.gov/11447388/
- Probiotics — Health Professional Fact Sheet. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Probiotics-HealthProfessional/