Bifidobacterium lactis
Also called B. lactis, Bifidobacterium animalis subsp. lactis, B. animalis lactis, HN019, BB-12, Bl-04.
Best grade C across 10 graded outcomes Other Last checked
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The short answer
From 15 sourcesB. lactis is one of the most tested probiotics, but results depend on strain and setting. A 2022 meta-analysis found a small rise in bowel movement frequency, yet three larger HN019 constipation trials missed their main outcomes. Bl-04 did not lower rhinovirus colds, and BLa80 findings on sleep and childhood eczema await replication.
Every graded outcome on this page
10 rows · line = participants- CGrade CDefecation frequency and gut comfort in adults with infrequent bowel movementsBowel habitsn 1,248
- CGrade CEczema in young children (strain BLa80)Eczeman 360
- CGrade CSleep quality in healthy adults (strain BLa80)Sleepn 101
- CGrade CWhole-gut transit time in adults with functional gut symptomsBowel habitsn 100
- DGrade DCrying time in infant colic (strain BB-12)Infant colicn 78
- DGrade DConstipation symptoms in functional constipation (strain BL-99)Constipationn 41
- ∅No effectRhinovirus colds after a controlled virus challengeColdsn 334
- ∅No effectComplete spontaneous bowel movements in functional constipationConstipationn 229
- ∅No effectColonic transit time and constipation symptoms in functional constipationConstipationn 228
- ∅No effectComplete spontaneous bowel movements in functional constipationConstipationn 224
- 7 more graded outcomes, in the evidence chapter
Key facts
- What it is
- A probiotic subspecies; trials name the strain (HN019, BB-12, Bl-04, BLa80, BL-99), and results differ by strain1469
- Bowel frequency (pooled)
- A 2022 meta-analysis of 13 trials in healthy adults found a small rise in defecation frequency (SMD 0.26); pain and bloating did not change3
- Constipation trials
- Three HN019 trials in adults with functional constipation (228, 229 and 224 people) missed their main outcomes578
- Colds (Bl-04)
- No fewer rhinovirus colds than placebo after a controlled virus challenge9
- Young children (BLa80)
- In 360 children aged 0–3, 3 months of BLa80 was followed by less eczema over 6 months (26.1% vs 66.7% on placebo)13
What it is
Bifidobacterium lactis (B. animalis subsp. lactis) is a probiotic bacterium; studied strains include HN019, BB-12 and Bl-04.
Forms, side by side
4 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.
Bifidobacterium lactis forms compared
4 forms| 4 forms | HN019 (capsules or powder) | BB-12 (capsules, yogurts) | Bl-04 (often in multi-strain blends) | BLa80 (capsules or sachets) |
|---|---|---|---|---|
| Absorption in people | Not absorbed; probiotics act in the gut. Trials measured gut transit, stool frequency and stool markers.48 | Not absorbed; acts in the gut.6 | Not absorbed; acts in the gut.9 | Not absorbed; acts in the gut. BLa80 changed stool bacteria in the sleep and child trials.1314 |
| GI tolerance | No adverse events in a 100-person, 14-day trial; three adverse events judged unlikely to be related in a 228-person trial.45 | In a meta-analysis of placebo-controlled BB-12 trials, adverse-event rates were 15.2% on BB-12 and 14% on placebo; half of the trials did not report adverse events.10 | No adverse events judged definitely or probably related in the 28-day rhinovirus trial.9 | No serious adverse events in 360 children aged 0–3 over 3 months.13 |
| Studied for | Gut transit time and functional constipation | Defecation frequency in adults with infrequent bowel movements; colic in breastfed infants (drops) | Rhinovirus colds | Sleep quality in adults; eczema in young children |
- HN019 (capsules or powder)
- Absorption in people
- Not absorbed; probiotics act in the gut. Trials measured gut transit, stool frequency and stool markers.48
- GI tolerance
- No adverse events in a 100-person, 14-day trial; three adverse events judged unlikely to be related in a 228-person trial.45
- Studied for
- Gut transit time and functional constipation
- BB-12 (capsules, yogurts)
- Absorption in people
- Not absorbed; acts in the gut.6
- GI tolerance
- In a meta-analysis of placebo-controlled BB-12 trials, adverse-event rates were 15.2% on BB-12 and 14% on placebo; half of the trials did not report adverse events.10
- Studied for
- Defecation frequency in adults with infrequent bowel movements; colic in breastfed infants (drops)
- Bl-04 (often in multi-strain blends)
- BLa80 (capsules or sachets)
What the human research says
Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.
Trial map
10 graded outcomes, largest study first10 graded outcomes: 5 improved, 1 mixed, 4 no effect. The largest, a 2015 randomized trial of 1,248 people on defecation frequency and gut comfort in adults with infrequent bowel movements, found mixed results.
1Defecation frequency and gut comfort in adults with infrequent bowel movements
Mixed · Grade C · RCT, 1,248 people, 2015
Healthy adults with low defecation frequency and abdominal discomfort
Dose, result and source| Outcome | Found | People | Study | Who was studied |
|---|---|---|---|---|
| Defecation frequency and gut comfort in adults with infrequent bowel movements | Mixed | 1,248 | Grade C · RCT, 2015 | Healthy adults with low defecation frequency and abdominal discomfort |
| Eczema in young children (strain BLa80) | Improved | 360 | Grade C · RCT, 2026 | Healthy children aged 0–3 years (China) |
| Rhinovirus colds after a controlled virus challenge | No effect | 334 | No-effect grade · RCT, 2022 | Healthy volunteers at a US university (165 Bl-04, 169 placebo randomized) |
| Complete spontaneous bowel movements in functional constipation | No effect | 229 | No-effect grade · RCT, 2024 | Adults aged 18 to 70 with functional constipation at 5 hospitals in Shanghai (85% female) |
| Colonic transit time and constipation symptoms in functional constipation | No effect | 228 | No-effect grade · RCT, 2018 | Adults with functional constipation (Rome III criteria) in France |
| Complete spontaneous bowel movements in functional constipation | No effect | 224 | No-effect grade · RCT, 2025 | Adults with functional constipation (Rome III) at four clinical units in France |
| Sleep quality in healthy adults (strain BLa80) | Improved | 101 | Grade C · RCT, 2025 | Healthy young adults aged 19–45 (mean age about 20) with poor baseline sleep (PSQI about 11.5) |
| Whole-gut transit time in adults with functional gut symptoms | Improved | 100 | Grade C · RCT, 2011 | Adults with functional gastrointestinal symptoms (mean age 44, 64% female) |
| Crying time in infant colic (strain BB-12) | Improved | 78 | Grade D · RCT, 2026 | Exclusively breastfed term infants with colic |
| Constipation symptoms in functional constipation (strain BL-99) | Improved | 41 | Grade D · RCT, 2026 | Adults with functional constipation |
Every graded row
10 rowsShowing 10 of 10 outcomes. Human trials only.
CGrade CDefecation frequency and gut comfort in adults with infrequent bowel movementsBowel habitsMore bowel movements; comfort unchangedRCT
n 1,248 · 2015
Mixed Global relief of abdominal discomfort did not differ and the main responder analysis missed significance (OR 1.31, P=0.071); a stricter responder definition (OR 1.55) and average defecation frequency favoured BB-12. Both doses worked similarly.
- Design
- RCT, n = 1,248, 2015
- Population
- Healthy adults with low defecation frequency and abdominal discomfort
- Form
- BB-12 capsules
- Dose
- 1 billion or 10 billion CFU a day
- Duration
- 4 weeks
- Source
- Reference 6 · PubMed 26382580 (opens PubMed)
CGrade CEczema in young children (strain BLa80)EczemaImprovedRCT
n 360 · 2026
Improved Eczema over 6 months, the primary outcome: 26.1% (47 of 180) vs 66.7% (120 of 180) on placebo by intention to treat; 30.1% vs 73.2% per protocol. No serious adverse events in either group.
- Design
- RCT, n = 360, 2026
- Population
- Healthy children aged 0–3 years (China)
- Form
- B. animalis subsp. lactis BLa80 sachets
- Dose
- 5 × 10⁹ CFU a day
- Duration
- 3 months, then 3 months of follow-up
- Source
- Reference 13 · PubMed 41167178 (opens PubMed)
CGrade CSleep quality in healthy adults (strain BLa80)SleepImprovedRCT
n 101 · 2025
Improved The PSQI total score fell more than with placebo, indicating better self-rated sleep quality.
- Design
- RCT, n = 101, 2025
- Population
- Healthy young adults aged 19–45 (mean age about 20) with poor baseline sleep (PSQI about 11.5)
- Form
- B. animalis subsp. lactis BLa80 in maltodextrin
- Dose
- 10 billion CFU a day
- Duration
- 8 weeks
- Source
- Reference 14 · PubMed 40169760 (opens PubMed)
CGrade CWhole-gut transit time in adults with functional gut symptomsBowel habitsFaster gut transitRCT
n 100 · 2011
Improved Transit time fell from 49 to 21 hours on the high dose and from 60 to 41 hours on the low dose, but not on placebo (43 to 44 hours); eight of nine symptoms fell in frequency on the high dose vs two on placebo. No adverse events.
- Design
- RCT, n = 100, 2011
- Population
- Adults with functional gastrointestinal symptoms (mean age 44, 64% female)
- Form
- HN019 capsules
- Dose
- 17.2 billion or 1.8 billion CFU a day
- Duration
- 14 days
- Source
- Reference 4 · PubMed 21663486 (opens PubMed)
DGrade DCrying time in infant colic (strain BB-12)Infant colicImprovedRCT
n 78 · 2026
Improved At 60 days, mean crying time, vomiting episodes and number of defecations were lower in the BB-12 group than with placebo (P < 0.05).
- Design
- RCT, n = 78, 2026
- Population
- Exclusively breastfed term infants with colic
- Form
- B. animalis subsp. lactis BB-12 drops
- Dose
- 5 drops a day (CFU not stated in the abstract)
- Duration
- 6 weeks, assessed up to 60 days
- Source
- Reference 12 · PubMed 42775119 (opens PubMed)
DGrade DConstipation symptoms in functional constipation (strain BL-99)ConstipationImprovedRCT
n 41 · 2026
Improved PAC-SYM constipation symptom scores fell more than with placebo, notably abdominal discomfort (change 1.8 vs 0.9, p = 0.007) and pain during defecation (2.1 vs 1.0, p = 0.003); the gains persisted 2 weeks after stopping.
- Design
- RCT, n = 41, 2026
- Population
- Adults with functional constipation
- Form
- B. animalis subsp. lactis BL-99
- Dose
- 1 × 10¹¹ CFU a day
- Duration
- 4 weeks, then 2 weeks of follow-up
- Source
- Reference 11 · PubMed 42751774 (opens PubMed)
∅No effectRhinovirus colds after a controlled virus challengeColdsNo fewer coldsRCT
n 334 · 2022
No effect Rhinovirus-associated illness occurred in 63 of 112 people (56%) on Bl-04 and 60 of 120 (50%) on placebo (p = 0.34).
- Design
- RCT, n = 334, 2022
- Population
- Healthy volunteers at a US university (165 Bl-04, 169 placebo randomized)
- Form
- Bl-04
- Dose
- Daily dose not stated in the abstract
- Duration
- 28 days before rhinovirus challenge, then 14 days of follow-up
- Source
- Reference 9 · PubMed 34927036 (opens PubMed)
∅No effectComplete spontaneous bowel movements in functional constipationConstipationNo difference from placeboRCT
n 229 · 2024
No effect Weekly complete spontaneous bowel movements rose by 0.80 with HN019 and 0.66 with placebo, with no difference between groups.
- Design
- RCT, n = 229, 2024
- Population
- Adults aged 18 to 70 with functional constipation at 5 hospitals in Shanghai (85% female)
- Form
- HN019 in maltodextrin
- Dose
- About 7.0 billion CFU a day at the start (4.69 billion at the end)
- Duration
- 8 weeks
- Source
- Reference 7 · PubMed 39356506 (opens PubMed)
∅No effectColonic transit time and constipation symptoms in functional constipationConstipationNo change in the main analysisRCT
n 228 · 2018
No effect No difference from placebo in colonic transit time or any secondary outcome. In a post hoc subgroup of 65 people with 3 or fewer bowel movements a week, weekly movements rose by 2.0 (high dose) and 1.7 (low dose).
- Design
- RCT, n = 228, 2018
- Population
- Adults with functional constipation (Rome III criteria) in France
- Form
- HN019 capsules
- Dose
- 1 billion or 10 billion CFU a day
- Duration
- 28 days
- Source
- Reference 5 · PubMed 29227175 (opens PubMed)
∅No effectComplete spontaneous bowel movements in functional constipationConstipationNo difference from placeboRCT
n 224 · 2025
No effect HN019 was not superior to placebo for complete spontaneous bowel movements; stool moisture, microbiota, metabolites and calprotectin did not differ. No safety concerns were identified.
- Design
- RCT, n = 224, 2025
- Population
- Adults with functional constipation (Rome III) at four clinical units in France
- Form
- HN019
- Dose
- Daily dose not stated in the abstract
- Duration
- 8 weeks
- Source
- Reference 8 · PubMed 40320938 (opens PubMed)
What the numbers add up to
Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.
Bigger trials, smaller effects
Maker-funded evidence
Studied doses
Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.
Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.
Doses studied in human trials
Doses studied in human trials ranged from 1 billion CFU a day of BB-12 or HN019 for 4 weeks to 100 billion CFU a day of BL-99 for 4 weeks; HN019 was also tested at 17.2 billion CFU a day for 14 days, BLa80 at 10 billion CFU a day for 8 weeks in adults and 5 billion CFU a day for 3 months in young children.4567111314
Interactions and safety
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
What Bifidobacterium lactis meets
1 cited row 1 tested togetherMedicines 1
Supplements and foods 1
- Drug label or FDA notice
- Tested together in a graded trial
Choose a medicine or supplement above to read its cited rows here.
Also cited: 1 tested together
Antibiotics
Drug labelDrug label or FDA notice
Antibiotics, for example any oral antibiotic course: Health Canada's probiotic monograph requires labels for bacterial probiotics, including B. animalis subsp. lactis, to direct use at least 2–3 hours before or after antibiotics.
Source 1, Health Canada, Natural and Non-prescription Health Products Directorate (2026)
L. rhamnosus GR-1 and L. reuteri RC-14L. rhamnosus GR-1 and L. reuteri RC-14 page
Tested together
Urinary tract infections after spinal cord injury. Graded on the L. rhamnosus GR-1 and L. reuteri RC-14 page; tested together is not a claim that they work better together.
Interactions
1 agent| Agent | What the source says | Evidence |
|---|---|---|
| Medicines1 | ||
| Antibioticse.g. any oral antibiotic course | Health Canada's probiotic monograph requires labels for bacterial probiotics, including B. animalis subsp. lactis, to direct use at least 2–3 hours before or after antibiotics.1 | Drug label |
Check with what you take
Kept on this device onlyAdd what you take. We list every interaction our evidence profiles cite between Bifidobacterium lactis and your picks, and between your picks.
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Add a supplement or medicine you take to check it against Bifidobacterium lactis.
Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.
Who should be careful
4 groups- Immune-compromised conditions
- Health Canada's probiotic monograph: do not use if you have an immune-compromised condition (for example AIDS, lymphoma, or long-term corticosteroid treatment).1
- Fever or severe gut symptoms
- Health Canada: ask a health care practitioner before use if you have fever, vomiting, bloody diarrhoea or severe abdominal pain, and stop if digestive upset occurs, worsens or lasts beyond 3 days.1
- Premature infants and seriously ill people
- NCCIH reports severe or fatal infections in premature infants given probiotics, and higher risk in people with severe illness.2
- Pregnancy and breastfeeding
- LactMed has no probiotic entry. In the SPRING trial, 411 overweight or obese pregnant women took L. rhamnosus plus B. lactis (strains not named in the abstract) from the second trimester: gestational diabetes was no less common (18.4% vs 12.3% on placebo), fasting glucose was slightly higher (79.3 vs 77.5 mg/dL), and preeclampsia was 9.2% vs 4.9% (P = 0.09).15
How to read the label
What to check on the Supplement Facts panel.
How to read the label
2 checksLook for the strain code
Where to buy Bifidobacterium lactis
Products from brands we partner with that contain Bifidobacterium lactis. Check the amount per serving against the doses studied above, and the label for other ingredients.
Bifidobacterium lactis products from partner brands
2 products Paid links · we earn a commission- HerbsProNOW Foods Probiotic-10, 25 Billion, 30 Veg Caps
1 capsule: 25 billion CFU of a 10-strain blend that includes B. lactis Bl-04 (per-strain amounts not listed); the single-strain trials here did not test this blend
$11.16one-timeChecked Oct 15, 2026 - Physician’s ChoicePhysician’s Choice 60 Billion Probiotic (30 capsules)
1 capsule: 60 billion CFU at expiration from a 10-strain blend of lactobacilli and bifidobacteria (220 mg) that includes B. lactis Bl-04, plus a 150 mg organic inulin and acacia fiber prebiotic blend; the label lists species only and gives no count per strain (the strain codes are on the brand’s product page); 30 servings
$29.38one-timeChecked Oct 20, 2026
Frequently asked questions
Short answers to common questions; the numbers link to the sources below.
Common questions
7 answersDoes B. lactis help constipation?
Does it speed up digestion?
Does B. lactis help with colds?
Bl-04 did not lower rhinovirus colds in a controlled virus-challenge trial.9
Does B. lactis help colic in babies?
One trial in 78 exclusively breastfed term infants found less crying with BB-12 drops than placebo at the 60-day follow-up of a 6-week course (grade D). It has not been repeated.12
Is B. lactis safe?
How long does B. lactis take to work?
Can B. lactis be taken with antibiotics?
Health Canada's probiotic monograph says bacterial probiotics, B. lactis included, should be taken at least 2–3 hours before or after antibiotics.1
Sources
15 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.
Sources cited on this page
15 sources- 1Probiotics (Natural Health Product monograph, April 24, 2026)Guideline Health Canada, Natural and Non-prescription Health Products Directorate, 2026 · webprod.hc-sc.gc.ca
- 2Probiotics: Usefulness and SafetyFact sheet National Center for Complementary and Integrative Health (NCCIH), 2019 · nccih.nih.gov
- 3Effects of Bifidobacterium animalis subspecies lactis supplementation on gastrointestinal symptoms: systematic review with meta-analysis.Meta-analysis Nutr Rev, 2022 · PMID 34918142
- 4Dose-response effect of Bifidobacterium lactis HN019 on whole gut transit time and functional gastrointestinal symptoms in adults.RCT Scand J Gastroenterol, 2011 · PMID 21663486
- 5Effects of 28-day Bifidobacterium animalis subsp. lactis HN019 supplementation on colonic transit time and gastrointestinal symptoms in adults with functional constipation: A double-blind, randomized, placebo-controlled, and dose-ranging trial.RCT Gut Microbes, 2018 · PMID 29227175
- 6Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial.RCT Br J Nutr, 2015 · PMID 26382580
- 7Eight-Week Supplementation With Bifidobacterium lactis HN019 and Functional Constipation: A Randomized Clinical Trial.RCT JAMA Netw Open, 2024 · PMID 39356506
- 8Effect of an 8-Week Bifidobacterium lactis HN019 Supplementation on Functional Constipation: A Multi-Center, Triple-Blind, Randomized, Placebo-Controlled Trial.RCT Mol Nutr Food Res, 2025 · PMID 40320938
- 9Effect of Bifidobacterium animalis spp. lactis Bl-04 on Rhinovirus-Induced Colds: A Randomized, Placebo-Controlled, Single-Center, Phase II Trial in Healthy Volunteers.RCT EClinicalMedicine, 2022 · PMID 34927036
- 10Safety of One of the Most Commonly Used Probiotic Strains: Systematic Review and Meta-analysis of Reported Adverse Events.Meta-analysis Probiotics Antimicrob Proteins, 2026 · PMID 40892162
- 11Efficacy of Bifidobacterium animalis subsp. lactate BL-99 in relieving functional constipation: a randomized placebo-controlled clinical trial.RCT Food Funct, 2026 · PMID 42751774
- 12The Efficacy of the Administration of Bifidobacterium lactis for Treatment of Infantile Colic: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial.RCT Adv Biomed Res, 2026 · PMID 42775119
- 13Bifidobacterium animalis subsp. lactis BLa80 for preventing allergic, respiratory, and gastrointestinal diseases in young children in China: a randomized double-blind placebo-controlled trial.RCT Clin Exp Pediatr, 2026 · PMID 41167178
- 14A double blinded randomized placebo trial of Bifidobacterium animalis subsp. lactis BLa80 on sleep quality and gut microbiota in healthy adults.RCT Sci Rep, 2025 · PMID 40169760
- 15Probiotics for the Prevention of Gestational Diabetes Mellitus in Overweight and Obese Women: Findings From the SPRING Double-Blind Randomized Controlled Trial.RCT Diabetes Care, 2019 · PMID 30659070
What changed
Every dated change to this page: what changed, who made it and why.
Change log
3 entries| Date | Change | Who and why |
|---|---|---|
| evidence, key facts, summary, studied doses, interactions, who should avoid, forms, FAQ, questions, related | Removed the 2022 meta-analysis as a graded row because its n was a trial count (13 trials; participant total not in the abstract, no PMC full text) and kept it as a key fact. Added four strain-named trials: BL-99 for functional constipation (2026, 41 people, grade D), BB-12 drops for infant colic (2026, 78 infants, grade D), BLa80 in 360 young children for eczema (2026, grade C; respiratory-infection figures internally inconsistent in the abstract and not used) and BLa80 for sleep (2025, 101 adults, grade C; n from full text). Added the Health Canada antibiotic-spacing direction, a pregnancy note citing the SPRING trial (LactMed and LiverTox have no probiotic entry), a BLa80 form row, FAQ items on antibiotics, colic and time to effect, page questions and links. Not added: a 46-person BLa80 constipation trial and an 80-person BLa80 diabetes trial (analysed n and dose not in the abstracts), and multi-strain blends. | Writer: Kymata Health EditorialTrigger: A–Z audit against docs/supplements/AUDIT-STANDARD.md |
| where to buy | Added a 10-strain probiotic that includes B. lactis Bl-04, with its label amounts and the one-time price on the brand’s own page; it is listed as a blend because the label gives no count per strain. | Writer: Kymata Health EditorialTrigger: product listing added |
| all | Initial editorial evidence review. Every PMID checked against NCBI E-utilities esummary (title, year, journal; none retracted) and each cited abstract read; numbers taken from the abstracts (full text or registry used only where noted). Funding disclosed per study: Fonterra Research Centre (2011, full text), E.I. DuPont (2018, full text), Chr. Hansen authors (2015, abstract affiliations), Danisco China/IFF (2024, full text), Danisco Sweeteners Oy/IFF (2025 PubMed grant field; 2022 abstract); the 2022 and 2026 meta-analyses name no funder. 2025 trial n from ClinicalTrials.gov NCT04231162. Safety rows use only Health Canada and NCCIH. Where to buy: NOW Foods Probiotic-10 (label checked 2026-10-15). | Writer: Kymata Health EditorialTrigger: new page |
Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.