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📰Read the full Lactobacillus evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ STRAIN-SPECIFIC evidence: LGG ≠ L. acidophilus ≠ L. reuteri [2]
⚠ Start probiotics within 48 hours of antibiotic initiation; separate by 2+ hours [2]
⚠ Severely immunocompromised: rare Lactobacillus bacteremia risk [1]
⚠ L. reuteri DSM 17938 for breastfed infant colic — 100 million CFU (low dose!) [2]
ℹ️ Not obtained from food. Not applicable — obtained from fermented foods rather than measured toward a daily microgram/milligram target.
🔬 Lab interpreter
ℹ️ No validated blood test. There is no established laboratory test to assess status or guide dosing for this ingredient. Clinical response and symptoms are the practical guide.
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
STRAIN SPECIFICITY is the #1 rule of probiotics — 'Lactobacillus' alone means nothing. LGG: best for AAD (meta-analysis). L. reuteri DSM 17938: best for infant colic (reduces crying 50 min/day). L. plantarum 299v: IBS. Always check the strain code, not just genus/species. Avoid live probiotics in severely immunocompromised patients [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
Specific strains (LGG, L. rhamnosus HN001) studied safely in pregnancy [2].
👦 Pediatric: Specific dosage data under clinical review
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: With or without food (strain-dependent). LGG: with food [2].
💊 With food: Some strains survive better with food [2].
🚫 Avoid: Live probiotics in severely immunocompromised [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['L. rhamnosus GG (LGG, Culturelle)', 'preferred', 'Most studied strain globally. Best evidence for AAD and pediatric diarrhea [2].'] | Standard | Check label | |
| ['L. acidophilus (various strains)', 'common', 'Found in most yogurts and probiotic supplements [1].'] | Standard | Check label | |
| ['L. reuteri DSM 17938 (BioGaia)', 'preferred', 'Best evidence for infantile colic (reduces crying by 50%) [2].'] | Standard | Check label | |
| ['L. plantarum 299v', '', 'Evidence for IBS symptom reduction [2].'] | Standard | Check label | |
| ['Multi-strain Lactobacillus blends', 'common', 'Common in commercial products. Evidence varies [1].'] | Standard | Check label |
3 Common questions
Does the strain really matter? ▼
YES — this is the single most important concept in probiotics. LGG is proven for AAD; L. reuteri DSM 17938 for colic. A random 'Lactobacillus acidophilus' product with no strain code has uncertain evidence [2].
Should I take probiotics with antibiotics? ▼
Yes — meta-analyses support starting probiotics within 48 hours of antibiotic initiation and continuing for 1–2 weeks after completion. Separate probiotic and antibiotic doses by 2+ hours [2].
Are yogurt probiotics enough? ▼
Yogurt provides live Lactobacilli but at lower, unstandardized doses. For therapeutic purposes (AAD prevention, IBS), standardized supplements with defined strains and CFU counts are preferred [1].
Can probiotics cause infection? ▼
In healthy individuals: essentially zero risk. In severely immunocompromised patients (neutropenia, ICU, short bowel syndrome): rare cases of Lactobacillus bacteremia have been reported [1]. Avoid live probiotics in severely immunocompromised patients.
4 Clinical evidence
Strong
AAD (antibiotic-associated diarrhea): meta-analysis — LGG and S. boulardii are the best-evidenced probiotics for AAD prevention (NNT=13) [2]. Infantile colic: L. reuteri DSM 17938 reduces crying time by ~50 minutes/day in breastfed infants (meta-analysis) [2]. Effects are STRAIN-SPECIFIC: genus-level recommendations are insufficient [2]. HIGH
Moderate
Acute infectious diarrhea (children): LGG reduces duration by ~1 day [2]. C. difficile prevention: some evidence for LGG and S. boulardii alongside antibiotics [2]. IBS: L. plantarum 299v improved bloating and pain in RCTs [2]. Vaginal health: L. rhamnosus and L. reuteri for BV prevention [2]. Atopic dermatitis prevention: LGG during pregnancy and infancy reduced AD incidence in some trials [2]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Relative
⚠ Immunocompromised patients — rare cases of Lactobacillus bacteremia
⚠ D-lactic acidosis in short bowel syndrome (L. acidophilus is a D-lactate producer)
⚠ Concurrent antibiotics — take 2+ hours apart
🚩 Red flags
● Severely immunocompromised patient — bacteremia risk with live probiotics [1]
● Product without strain code — unknown evidence base [2]
6 Interactions
Drug interactions
Antibiotics Minor (timing)
Mechanism: Antibiotics kill Lactobacilli. [2]
Effect: Reduced probiotic efficacy if taken simultaneously. [2]
Action: Separate by 2+ hours. Continue probiotics throughout and 1–2 weeks after antibiotic course [2].
Supplement synergies
Prebiotics (FOS, inulin) · 3–5 g/day prebiotics
Feed probiotic bacteria. Synbiotic effect [1].
Feed probiotic bacteria. Synbiotic effect [1].
S. boulardii · 250–500 mg S. boulardii
Yeast probiotic (unaffected by antibiotics) + Lactobacillus for comprehensive AAD prevention [2].
Yeast probiotic (unaffected by antibiotics) + Lactobacillus for comprehensive AAD prevention [2].
7 Regulatory
United States (FDA): GRAS. Dietary supplement. NOT FDA-approved as drug (despite strong evidence for some indications) [1].
European Union (EFSA): No authorized health claims for probiotics (EFSA rejected all probiotic health claim applications). Products cannot be labeled 'probiotic' in some EU markets [1].
South Korea: Registered health functional food ingredient.
AGA/WGO: Clinical practice guidelines recommend specific strains for specific indications [2].
8 US supplement products
39
on-market products containing Lactobacillus (NIH DSLD)
Brands carrying Lactobacillus (29)
Click a brand to see its Lactobacillus products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. Lactobacillus — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 15]. Available from: https://supplement.ge/ingredients/lactobacillus/
APA 7th: Pkhakadze, G. (2026). Lactobacillus — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/lactobacillus/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: February 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Lactobacillus — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/lactobacillus/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG