Moderate evidenceGut health

Bifidobacterium Bifidum

One of the few probiotic species with a well-replicated IBS result: the MIMBb75 strain improved symptoms in two randomized trials, including a heat-inactivated version. Other claims are weaker.

Evidence last reviewed: August 2026

View on iHerb Ships to 180+ countries · welcome discount for new customers

What the science says

IBS symptoms Moderate evidence
A randomized, double-blind, placebo-controlled trial of B. bifidum MIMBb75 significantly alleviated IBS symptoms and improved quality of life. A larger multicentre randomized trial of the heat-inactivated strain reproduced the benefit, which is unusual in probiotic research.
Respiratory infections Limited evidence
A double-blind randomized trial of a multi-strain product containing B. bifidum MF 20/5 reported shorter common cold episodes, but the effect cannot be attributed to B. bifidum alone.
Metabolic markers Limited evidence
Small randomized trials of specific strains such as BGN4 report changes in gut permeability markers and inflammatory measures in adults with excess adiposity; these are single studies with surrogate endpoints.

Dosage & safety

Studied doseThe MIMBb75 trials used about 1 billion CFU per day, taken as a single daily capsule for 4–8 weeks. Strain matters more than the count.

SafetyWell tolerated, with adverse event rates similar to placebo in trials. The heat-inactivated form is an option for people who prefer not to take live organisms. Caution with live probiotics in severe immunosuppression or critical illness.

Scientific references

Randomised clinical trial: Bifidobacterium bifidum MIMBb75 significantly alleviates irritable bowel syndrome and improves quality of life--a double-blind, placebo-controlled study
Guglielmetti S, Mora D, Gschwender M, Popp K — Aliment Pharmacol Ther, 2011
Heat-inactivated Bifidobacterium bifidum MIMBb75 (SYN-HI-001) in the treatment of irritable bowel syndrome: a multicentre, randomised, double-blind, placebo-controlled clinical trial
Andresen V, Gschossmann J, Layer P — Lancet Gastroenterol Hepatol, 2020
Effect of Lactobacillus gasseri PA 16/8, Bifidobacterium longum SP 07/3, B. bifidum MF 20/5 on common cold episodes: a double blind, randomized, controlled trial
de Vrese M, Winkler P, Rautenberg P, Harder T, Noah C, Laue C, Ott S, Hampe J, Schreiber S, Heller K, Schrezenmeir J — Clin Nutr, 2005

Where to buy

View on iHerb

Ships to 180+ countries · welcome discount for new customers

Referral link — this site may earn a commission on purchases.

Related in Gut health

Probiotics Moderate evidence
Psyllium Husk (fiber) Strong evidence
L-Glutamine Limited evidence
Oregano Oil Limited evidence
Ginger Moderate evidence
Inulin (Prebiotic Fiber) Moderate evidence