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Dietary supplement

B. Longum Ingredients & Drug Interactions

by Custom Probiotics

B. Longum label
See full label image
Powder Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking B. Longum against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

B. Longum is a dietary supplement by Custom Probiotics with 1 active ingredient. Its ingredients are commonly taken for digestive health and regularity, irritable bowel syndrome (ibs), diarrhea (including antibiotic-related).Based on those ingredients, 182 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are B. longum. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against B. Longum by Custom Probiotics

Ask about any prescription or over-the-counter medication and we check it for interactions with B. Longum by Custom Probiotics — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of B. Longum by Custom Probiotics

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 16, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 1 active ingredient.

Custom Probiotics B. Longum contains one active ingredient: Bifidobacterium longum, a live beneficial bacterium intended to support digestive health.

There are no inactive ingredients listed — this is a single-organism probiotic powder with nothing else added.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Bifidobacterium Longum's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: digestive health and probiotic support.
  • We looked for evidence on: Antibiotic-associated diarrhea, Constipation, Diarrhea, Irritable bowel syndrome (IBS), Lactose intolerance, Rotaviral diarrhea — and 3 related terms.
  • The closest evidence on file: Bifidobacterium Longum is rated "Insufficient Reliable Evidence To Rate" for Antibiotic-associated diarrhea (Natural Medicines).
  • Also on file: Bifidobacterium Longum is rated "Insufficient Reliable Evidence To Rate" for Constipation, Diarrhea, Ulcerative colitis, Irritable bowel syndrome (IBS), and more.

The data we hold shows insufficient reliable evidence to rate B. longum for the conditions studied: age-related cognitive decline, hay fever, antibiotic-associated diarrhea, generalized anxiety, asthma, and athletic performance. That means the evidence so far hasn't been strong enough to confirm it works for these purposes.

If you're considering it for one of these reasons, talk it over with your doctor or pharmacist about what the current research actually supports.

The evidence, ingredient by ingredient Bifidobacterium Longum

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

B. longum is generally well tolerated in healthy people, but caution is warranted if you're seriously ill or have a weakened immune system — the data on safety in those situations is limited. Rare side effects when taken by mouth have included abdominal discomfort, bloating, flatulence, constipation, and one report of a dry cough.

There have been very rare cases of the organism entering the bloodstream (bacteremia) or causing infection in critically ill infants and adults, particularly in premature babies or those on life support. Regarding pregnancy and breastfeeding, the safety data rates B. longum as possibly safe, though the data are limited — check with your doctor before using it while breastfeeding.

Side effects, ingredient by ingredient Bifidobacterium Longum

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Bifidobacterium Longum.
  • The most serious interaction on file is rated Moderate.
  • For scale: 182 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Antibiotic drugs are the main medication type to watch: taking them at the same time as B. Longum can reduce the probiotic's effectiveness.

Separate your antibiotic and B. Longum doses by a few hours — your pharmacist can advise on timing that works with your dosing schedule.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

B. Longum may appeal to people looking for a straightforward single-strain probiotic, but the evidence for specific health claims isn't established yet.

It's generally well tolerated in healthy adults, but if you're seriously ill, immune-compromised, or pregnant or breastfeeding, talk with your doctor first. Most importantly, if you're on antibiotics, space them a few hours apart from this product so the antibiotic doesn't kill off the live organisms you're taking.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Sep 21, 2018.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about B. Longum, straight from the product label.

Brand Custom Probiotics
Net contents 0 Not Present
Market status On market
Date entered into DSLD Sep 21, 2018
DSLD ID 181262
Product type Non-nutrient/non-botanical
Supplement form Powder
Dietary claims / uses All Other
Intended target group(s) Children 4 or More Years of Age, Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for B. Longum by Custom Probiotics, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
0.1 Gram(s)
Maximum serving Sizes:
1.6 Gram(s)
IngredientAmount% DV
B. longum0 NP--

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Directions of use: Dissolve 1-2 scoops (enclosed) of the dairy-free probiotic powder in one glass of purified water and drink it. Do this first thing in the morning and/or at bedtime.

Please read enclosed dosage suggestions or visit www.customprobiotics.com

Storage

Bottles should be kept tightly closed and stored in the refrigerator to retain maximum potency.

Formulation

Does not contain: Artificial colors, flavors, preservatives, sugar, gluten, soy, wheat or FOS.

Dairy free probiotic powder

General Statements

Ultra potency

100 billion cfu's per gram

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

B. Longum by Custom Probiotics label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

B. Longum label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in B. Longum by Custom Probiotics

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size0.1 Gram(s) Dosage formPowder Amounts shown are per serving.

B. longum

Interacts with
182 drugs
0 NP per serving

Bifidobacterium longum is a 'friendly' bacterium found naturally in the human gut and used as a probiotic. It is generally well tolerated and is most...

B. longum monograph & interactions
Interaction report

B. Longum by Custom Probiotics Drug Interactions

Want to check YOUR meds against B. Longum?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
182Drugs
182 Moderate

Ingredients driving the most interactions

B. longum 182

Individual Drug Interactions

The ingredients in B. Longum interact with 182 drugs. Click any drug to see the details.

1 of the 1 ingredient in B. Longum interact with drugs. Each result below shows which ingredient is responsible. B. longum

Each ingredient & the kinds of drugs it affects

For each ingredient in B. Longum with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

B. longum1 drug type · 182 drugs

Antibiotic Drugs

Theoretically, taking Bifidobacterium longum with antibiotic drugs might decrease the effectiveness of B. longum.
Since B. longum preparations usually contain live and active organisms, simultaneously taking antibiotics might kill a significant number of the organisms. Tell patients to separate administration of antibiotics and B. longum preparations by at least 2 hours.

Likelihood Probable Evidence D
B. longum full monograph & interactions
The maker

Brand information

Manufacturer and brand details for B. Longum, from the product label.

Custom Probiotics

See all Custom Probiotics products
Name
Custom Probiotics, Inc.
City
Glendale
State
California
ZipCode
91214
Phone Number
(800) 219-8405
Web Address
www.customprobiotics.com
Pharmacist Counseling Corner

B. Longum by Custom Probiotics: Common Questions

Does B. Longum by Custom Probiotics interact with any medications?
Yes. Based on its ingredients, B. Longum has a known interaction with 182 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
B. Longum contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Do I need to refrigerate this powder?
The product facts provided don't include storage or handling instructions — check the label or contact the manufacturer for best practices on keeping the live organisms viable.
What's Bifidobacterium longum and what does it do?
B. longum is a beneficial live bacterium that's meant to support digestive health. However, the evidence we have isn't strong enough yet to confirm it works for specific conditions like allergies, anxiety, or athletic performance.
Can I take this while I'm on antibiotics?
Yes, but timing matters: antibiotics can kill the live organisms in this product if you take them together. Space your doses a few hours apart — your pharmacist can help you work out a schedule that fits with your antibiotic.
Is this safe to use if I'm immune-compromised or seriously ill?
Caution is needed. While B. longum is generally well tolerated in healthy people, there have been rare but serious cases of the organism entering the bloodstream in critically ill patients. Talk with your doctor before using it if you have a weakened immune system or serious illness.
Can I take B. Longum while breastfeeding?
The safety data rates it as possibly safe, but the information is limited. Check with your doctor before starting it so you can weigh the evidence together and make a decision that fits your situation.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if B. Longum is safe with your meds?

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

B. Longum label
Go deeper

The Full Monographs Behind B. Longum’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Bifidobacterium Longum

Interacts with 182 drugs

Bifidobacterium longum is a 'friendly' bacterium found naturally in the human gut and used as a probiotic. It is generally well tolerated and is most studied for digestive issues, though evi...

Read the full Bifidobacterium Longum monograph →
Sources

Sources & How We Checked

B. Longum's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 21 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Bifidobacterium Longum 21 references
  1. Ha GY, Yang CH, Kim H, Chong Y. Case of sepsis caused by Bifidobacterium longum. J Clin Microbiol 1999;37:1227-8.
  2. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
  3. Xiao JZ, Takahashi S, Odamaki T, et al. Antibiotic susceptibility of bifidobacterial strains distributed in the Japanese market. Biosci Biotechnol Biochem. 2010;74(2):336-42. PubMed
  4. Rautava S, Kainonen E, Salminen S, Isolauri E. Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant. J Allergy Clin Immunol. 2012;130(6):1355-60. PubMed
  5. Pruccoli G, Silvestro E, Pace Napoleone C, Aidala E, Garazzino S, Scolfaro C. Are probiotics safe? Bifidobacterium bacteremia in a child with severe heart failure. Infez Med. 2019;27(2):175-178.
  6. Pellonperä O, Vahlberg T, Mokkala K, et al. Weight gain and body composition during pregnancy: a randomised pilot trial with probiotics and/or fish oil. Br J Nutr. 2020 Nov 4:1-11. PubMed
  7. Pellonperä O, Mokkala K, Houttu N, et al. Efficacy of fish oil and/or probiotic intervention on the incidence of gestational diabetes mellitus in an at-risk group of overweight and obese women: A randomized, placebo-controlled, double-blind clinical trial PubMed
  8. Shahriari A, Karimi E, Shahriari M, Aslani N, Khooshideh M, Arab A. The effect of probiotic supplementation on the risk of gestational diabetes mellitus among high-risk pregnant women: A parallel double-blind, randomized, placebo-controlled clinical trial PubMed
  9. Esaiassen E, Hjerde E, Cavanagh JP, Simonsen GS, Klingenberg C; Norwegian Study Group on Invasive Bifidobacterial Infections. Bifidobacterium bacteremia: Clinical characteristics and a genomic approach to assess pathogenicity. J Clin Microbiol. 2017;55(7) PubMed
  10. Enomoto T, Sowa M, Nishimori K, et al. Effects of bifidobacterial supplementation to pregnant women and infants in the prevention of allergy development in infants and on fecal microbiota. Allergol Int 2014;63(4):575-85. PubMed
  11. US Food and Drug Administration (FDA). Dear Healthcare Provider Letter: Warning Regarding Use of Probiotics in Preterm Infants. September 2023. Available at: https://www.fda.gov/media/172606/download?attachment. Accessed November 1, 2023.
  12. Pillai A, Tan J, Paquette V, Panczuk J. Does probiotic bacteremia in premature infants impact clinically relevant outcomes? A case report and updated review of literature. Clin Nutr ESPEN. 2020;39:255-259. PubMed
  13. Sabaté JM, Iglicki F. Effect of Bifidobacterium longum 35624 on disease severity and quality of life in patients with irritable bowel syndrome. World J Gastroenterol 2022;28(7):732-744.
  14. Malaguarnera M, Greco F, Barone G, Gargante MP, Malaguarnera M, Toscano MA. Bifidobacterium longum with fructo-oligosaccharide (FOS) treatment in minimal hepatic encephalopathy: a randomized, double-blind, placebo-controlled study. Dig Dis Sci 2007;52(11) PubMed
  15. Zbinden A, Zbinden R, Berger C, Arlettaz R. Case series of Bifidobacterium longum bacteremia in three preterm infants on probiotic therapy. Neonatology 2015;107(1):56-9.
  16. Tamaki H, Nakase H, Inoue S, et al. Efficacy of probiotic treatment with Bifidobacterium longum 536 for induction of remission in active ulcerative colitis: A randomized, double-blinded, placebo-controlled multicenter trial. Dig Endosc 2016;28(1):67-74.
  17. Bertelli C, Pillonel T, Torregrossa A, et al. Bifidobacterium longum bacteremia in preterm infants receiving probiotics. Clin Infect Dis 2015;60(6):924-7. PubMed
  18. Esaiassen E, Cavanagh P, Hjerde E, Simonsen GS, Støen R, Klingenberg C. Bifidobacterium longum subspecies infantis bacteremia in 3 extremely preterm infants receiving probiotics. Emerg Infect Dis 2016;22(9):1664-6.
  19. Tena D, Losa C, Medina MJ, Sáez-Nieto JA. Peritonitis caused by Bifidobacterium longum: case report and literature review. Anaerobe 2014;27:27-30. PubMed
  20. Sangkanjanavanich S, Pradubpongsa P, Mitthamsiri W, Sangasapaviliya A, Boonpiyathad T. Bifidobacterium infantis 35624 efficacy in patients with uncontrolled asthma: A randomized placebo-controlled trial. Ann Allergy Asthma Immunol 2022;129(6):790-792. PubMed
  21. Wilson HL, Ong CW. Bifidobacterium longum vertebrodiscitis in a patient with cirrhosis and prostate cancer. Anaerobe 2017;47:47-50. PubMed

See these in context on the Bifidobacterium Longum monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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