Bacteriophage Prebiotics
Cocktails of E. coli-targeting viruses meant to prune unwanted gut bacteria. Two small trials from the same research group show measurable microbiome effects; clinical benefit remains unproven.
Evidence last reviewed: August 2026
What the science says
- Selective reduction of E. coli Limited evidence
A double-blind, placebo-controlled crossover trial in normal-to-overweight adults found 28 days of a bacteriophage cocktail reduced faecal E. coli without disrupting overall microbial diversity, alongside a small drop in circulating interleukin-4.
- Modest gut-symptom effects alongside a probiotic Limited evidence
A 4-week randomized, parallel-arm, double-blind, placebo-controlled trial in 68 adults reported that adding bacteriophages to Bifidobacterium lactis BL04 extended some self-reported gut health benefits. Both trials were small, in healthy people, and industry-funded.
- No clinical outcomes demonstrated Limited evidence
No trial has shown that bacteriophage supplements improve a diagnosed condition such as IBS, and the long-term consequences of routinely consuming lytic phages are unknown.
Dosage & safety
Scientific references
Where to buy
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