Moderate evidenceGut health

Enterococcus Faecium

A probiotic Enterococcus licensed as a medicine for diarrhoea in parts of Europe. The trial data for acute and antibiotic-associated diarrhoea are reasonable, but the species itself raises legitimate safety questions.

Evidence last reviewed: August 2026

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What the science says

Acute and antibiotic-associated diarrhoea Moderate evidence
An analysis of four previously unpublished studies of E. faecium SF68, including RCTs with 1,143 and 1,397 patients, found a shorter time to resolution of acute diarrhoea (median 3 versus 4 days) and fewer cases of antibiotic-associated diarrhoea (8.6% versus 16.2%).
Combination products for antibiotic-associated diarrhoea Moderate evidence
A meta-analysis of RCTs of live combined Bacillus subtilis and Enterococcus faecium found benefit for both treatment and prevention of antibiotic-associated diarrhoea, though the included trials are largely Chinese and of variable quality.
Tolerating H. pylori eradication therapy Limited evidence
A randomized, double-blind, placebo-controlled trial found E. faecium 129 BIO 3B-R reduced side effects of Helicobacter pylori eradication therapy in adults. This is a single trial.

Dosage & safety

Studied doseSF68 studies used capsules of roughly 7.5×10^7 CFU, two to three times daily for about 7 days.

SafetyThe caveat that matters: enterococci are opportunistic pathogens and can carry transferable antibiotic-resistance genes, which is why European safety assessment requires strain-level qualification. Use only characterised commercial strains, and avoid in immunosuppression, in people at risk of endocarditis such as those with prosthetic valves, and in critical illness.

Scientific references

Randomized, Placebo-Controlled, Double-Blind and Open-Label Studies in the Treatment and Prevention of Acute Diarrhea With Enterococcus faecium SF68
Greuter T, Michel MC, Thomann D — Front Med (Lausanne), 2020
Live Combined Bacillus Subtilis and Enterococcus Faecium for the Treatment and Prevention of Antibiotic-Associated Diarrhea: A RCT-Based Meta-Analysis
Zhang N, Chen Y, Shen Z — Tohoku J Exp Med, 2026
Impact of Enterococcus faecium 129 BIO 3B-R on Helicobacter pylori eradication therapy side effects in adult patients: a randomized, double-blind, placebo-controlled study
Tokunaga E, Inoue J, Asaji N — Sci Rep, 2025

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