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Supplement · Grade C

Bifidobacterium longum 1714 and medications.

Every documented pair, every citation. Below: 16 documented pairs grouped by mechanism.

Bifidobacterium longum 1714 is classified as a optimise supplement in the Distil database, evidence Grade C. The page below lists every medication we have explicitly assessed it against.

Bifidobacterium longum 1714 is a specific probiotic strain, sold commercially as Zenflore by PrecisionBiotics, studied for the gut-brain axis rather than digestion. In a small crossover trial in healthy volunteers, a daily dose of one billion CFU tended to lower cortisol output and subjective anxiety under acute stress, reduced daily reported stress, and produced subtle visuospatial memory changes. The evidence is Grade C and honest about its limits: one pilot study of 22 people and one IBS trial where 1714 was combined with another strain, so its individual contribution cannot be separated. It may support stress resilience as an adjunct, not as a primary anxiety treatment. The strain number matters: effects do not generalise to other B. longum strains, so the label must say 1714. On interactions, separate it from antibiotics by at least two hours, since they kill live bacteria, and prebiotic fibre like inulin or FOS may help sustain it. Anyone immunocompromised should check with their clinician first.

Below are the 16 documented pairs we have explicitly assessed for Bifidobacterium longum 1714: 6 amber and 10 green. The pairs cluster around 2 mechanisms: Immunosuppression caution and Probiotic timing with antibiotics. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.

Documented interactions

Last reviewed 15 June 2026. Each interaction below is assessed against PubMed-indexed evidence.

Immunosuppression caution

Amber Does interact with Azathioprine?

If you take azathioprine, it is sensible to check with your specialist before starting this strain: azathioprine dampens the immune system, often for an autoimmune condition or after a transplant, and in people whose defences are significantly weakened there have been rare cases of a probiotic organism getting into the bloodstream and causing an infection. Bifidobacterium longum 1714 is a live bacterium and safe for most people, but avoid it if you are seriously unwell in hospital or have a central line or drip.

Evidence: Supported by human study data.

Amber Does interact with Ciclosporin?

If you take ciclosporin, check with your specialist team before starting this strain: ciclosporin strongly dampens the immune system, usually after a transplant or for a serious autoimmune condition, and in people whose defences are this weakened there have been rare cases of a probiotic organism getting into the bloodstream and causing an infection. Bifidobacterium longum 1714 is a live bacterium and safe for most people, but avoid it if you are seriously unwell in hospital or have a central line or drip.

Evidence: Supported by human study data.

Amber Does interact with Everolimus?

If you take everolimus, check with your specialist team before starting this strain: everolimus strongly dampens the immune system, used after a transplant or in some cancers, and in people whose defences are this weakened there have been rare cases of a probiotic organism getting into the bloodstream and causing an infection. Bifidobacterium longum 1714 is a live bacterium and safe for most people, but avoid it if you are seriously unwell in hospital or have a central line or drip.

Evidence: Supported by human study data.

Amber Does interact with Methotrexate?

If you take methotrexate, it is sensible to check with your specialist before starting this strain: methotrexate dampens the immune system, and in people whose defences are significantly weakened there have been rare cases of a probiotic organism getting into the bloodstream and causing an infection. At the usual low weekly doses for arthritis or psoriasis this risk is small. Bifidobacterium longum 1714 is a live bacterium and safe for most people, but avoid it if you are seriously unwell in hospital or have a central line or drip.

Evidence: Supported by human study data.

Amber Does interact with Sirolimus?

If you take sirolimus, check with your specialist team before starting this strain: sirolimus strongly dampens the immune system, usually after a transplant, and in people whose defences are this weakened there have been rare cases of a probiotic organism getting into the bloodstream and causing an infection. Bifidobacterium longum 1714 is a live bacterium and safe for most people, but avoid it if you are seriously unwell in hospital or have a central line or drip.

Evidence: Supported by human study data.

Amber Does interact with Tacrolimus?

If you take tacrolimus, check with your specialist team before starting this strain: tacrolimus strongly dampens the immune system, usually after a transplant or for a serious autoimmune condition, and in people whose defences are this weakened there have been rare cases of a probiotic organism getting into the bloodstream and causing an infection. Bifidobacterium longum 1714 is a live bacterium and safe for most people, but avoid it if you are seriously unwell in hospital or have a central line or drip.

Evidence: Supported by human study data.

Probiotic timing with antibiotics

Green Does interact with Amoxicillin?

Bifidobacterium longum 1714 and amoxicillin are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your amoxicillin dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Amoxicillin

Green Does interact with Ciprofloxacin?

Bifidobacterium longum 1714 and ciprofloxacin are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your ciprofloxacin dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 29257353 · PMID 20458757 · BNF: Ciprofloxacin

Green Does interact with Clarithromycin?

Bifidobacterium longum 1714 and clarithromycin are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your clarithromycin dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 29257353 · PMID 20458757 · BNF: Clarithromycin

Green Does interact with Co-trimoxazole?

Bifidobacterium longum 1714 and co-trimoxazole are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your co-trimoxazole dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 29257353 · PMID 20458757 · BNF: Co-trimoxazole

Green Does interact with Doxycycline?

Bifidobacterium longum 1714 and doxycycline are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your doxycycline dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Doxycycline

Green Does interact with Erythromycin?

Bifidobacterium longum 1714 and erythromycin are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your erythromycin dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Erythromycin

Green Does interact with Metronidazole?

Bifidobacterium longum 1714 and metronidazole are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your metronidazole dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Metronidazole

Green Does interact with Minocycline?

Bifidobacterium longum 1714 and minocycline are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your minocycline dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Minocycline

Green Does interact with Nitrofurantoin?

Bifidobacterium longum 1714 and nitrofurantoin are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your nitrofurantoin dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Nitrofurantoin

Green Does interact with Trimethoprim?

Bifidobacterium longum 1714 and trimethoprim are fine to use together, and the strain may lower the chance of antibiotic-related diarrhoea. Bifidobacterium longum 1714 is a live bacterium, so space it about two hours away from your trimethoprim dose so the antibiotic does not reduce the live bacteria. The main exception is if your immune system is seriously weakened or you are critically ill in hospital, when any probiotic should be checked with your doctor first.

Evidence: Supported by human study data.

PMID 22570464 · PMID 20458757 · PMID 26756877 · BNF: Trimethoprim

What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.

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