About
What it is and where it shows up.
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host; 4 billion CFU (colony-forming units) denotes the viable cell count per serving dose. They are used in dietary supplements and functional foods to support gut microbiota balance, immune function, and digestive health, with common genera including Lactobacillus, Bifidobacterium, and Saccharomyces.
Safety summary
The regulatory and scientific consensus.
Probiotics are generally considered safe for healthy adults, with most common strains having a long history of safe food use; however, serious adverse events including bacteremia and fungemia have been reported in immunocompromised individuals, critically ill patients, and preterm infants. Safety is inherently strain-specific — the specific microorganism, dose, intended use, and vulnerability of the consumer together determine the risk profile. No universal acceptable daily intake (ADI) has been established; efficacy and safety are evaluated on a per-strain basis by regulatory authorities.
Regulatory landscape
What food-safety regulators have decided.
| Jurisdiction | Status | Note |
|---|---|---|
| EFSA (European Food Safety Authority) (European Union) | Restricted | Human probiotics are not regulated as a defined category and are not subject to EFSA's Qualified Presumption of Safety (QPS) assessment unless introduced as novel foods or genetically modified microorganisms. More than 400 health claim applications for probiotics submitted under Regulation (EC) No 1924/2006 have been rejected by EFSA due to insufficient evidence of cause-and-effect relationships. A single approved claim exists: yogurt cultures (≥10⁸ CFU/ml of L. delbrueckii subsp. bulgaricus and S. thermophilus) for improving lactose digestion in lactose maldigestion. Strain-level safety evaluated via QPS or full safety assessment for feed additives; similar assessment applied to novel food applications.source |
| FSSAI (Food Safety and Standards Authority of India) (India) | Approved | Regulated under FSS (Health Supplements, Nutraceuticals, Food for Special Dietary Use, Food for Special Medical Purpose, and Prebiotic and Probiotic Food) Regulations 2022. Probiotic food is defined as food with live micro-organisms that confer specified or demonstrated health benefits when ingested in adequate numbers as a single strain or combination. Probiotic properties must be scientifically substantiated; strain-specific approvals under FSS (Non-Specified Food and Food Ingredients) Regulations 2017 are required for novel strains. ICMR and DBT guidelines on probiotics serve as additional guidance. Labeling must declare viable cell count (CFU/g or CFU/ml) throughout shelf life.source |
| FDA (Food and Drug Administration) (United States) | Approved | Probiotics are not a defined regulatory product category under the FD&C Act. When sold as dietary supplements, they are classified as dietary ingredients (live microbials) under DSHEA 1994 and regulated by FDA's Center for Food Safety and Applied Nutrition (CFSAN). GRAS status is strain-specific and dose-specific; pre-market approval is not required for supplements, but manufacturers must notify FDA for novel dietary ingredients. FDA has issued specific safety warnings about probiotic use in preterm infants (<37 weeks gestation). CFU is an accepted unit of measure for labeling live microbial dietary supplements. |
Who should approach with care
Whose guidance would steer them away.
Infants — FDA (CFSAN, 2023) raised serious safety concerns about probiotic use in preterm infants (<37 weeks gestation) due to documented risk of probiotic sepsis; the American Academy of Pediatrics does not endorse routine use in this vulnerable population, particularly those with birth weight <1000g.
Other — Immunocompromised and critically ill individuals face elevated risk of bacteremia and fungemia; most serious reported complications (including Saccharomyces boulardii fungemia) have occurred in patients who are immunocompromised or have central venous catheters.
Ibd — Patients with inflammatory bowel disease may have compromised gut barrier integrity, and probiotic effects are highly strain-specific; medical supervision is recommended before initiating use.
Ibs — Evidence for probiotic efficacy in irritable bowel syndrome is inconsistent across strains and CFU doses; clinical guidance recommends strain-specific assessment before recommending use.
Lactose Intolerance — Certain probiotic products use dairy-based carrier matrices that may contain residual milk proteins or lactose; labeling should be checked and a healthcare provider consulted if dairy sensitivity is severe.
Research citations
The sources behind this verdict.
- 1FDA. Questions and Answers on Dietary Supplements. fda.gov
- 2EFSA. Qualified Presumption of Safety (QPS) — EFSA. efsa.europa.eu
- 3other. NIH Office of Dietary Supplements: Probiotics — Health Professional Fact Sheet, 2025. ods.od.nih.gov
- 4PubMed. Comparing technology and regulatory landscape of probiotics as food, dietary supplements and live biotherapeutics, 2024. pmc.ncbi.nlm.nih.gov
- 5FDA. Regulatory status of live microorganisms when used or intended for use in food (CFSAN Memorandum), 2023. fda.gov
- 6FSSAI. Food Safety and Standards (Health Supplements, Nutraceuticals, Food for Special Dietary Use, Food for Special Medical Purpose, and Prebiotic and Probiotic Food) Regulations, 2022, 2022. fssai.gov.in
Independently researched8 citations