Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii)

Probiotic microorganisms

ATC code: A07FA-PROBIOTICS(Probiotic microorganisms (generic group) – local code)

Brand names – drugs: Florastor

Brand names – supplements: Culturelle, Garden of Life Dr. Formulated ProbioticsSupplements are not tested in clinical trials and are not registered as medications.

Updated 24 Sep 2026 · Methodology

Indications

Antibiotic-associated diarrhoea

Adjunct

The 2019 Cochrane review (33 RCTs, more than 6,000 children) showed a reduction in antibiotic-associated diarrhoea in children from 19% to 8% with high-dose probiotics (at least 5 billion CFU daily) from day 1 of antibiotic therapy. In adults, the effect is less pronounced. The best evidence is for Lactobacillus rhamnosus GG and Saccharomyces boulardii strains. 2020 recommends Saccharomyces boulardii or Lactobacillus + Bifidobacterium combinations for prevention in children.

The effect is strain-specific. Use products with confirmed strain identity and adequate dose, not “ordinary yoghurt”.

Sources

ICD-10: K52.9 · ICD-11: ME05.1

Irritable bowel syndrome

Individual decision

Cochrane 2019 and 2020 rated the evidence base for probiotics in IBS as moderate with high strain-dependence. Some meta-analyses showed reduced pain and bloating. AGA 2020 does not recommend probiotics for IBS in adults outside clinical trials due to result heterogeneity and study quality. In some IBS-D patients, Bifidobacterium infantis 35624 or combination preparations provide clinical improvement.

Sources

ICD-10: K58.8 · ICD-11: DD91.0Z

Prevention of Clostridioides difficile infection recurrence

Individual decision

Cochrane 2017 showed a reduction in CDI on antibiotic therapy with probiotic use. However, 2021 and 2020 do not give an unambiguous recommendation – results are inconsistent across strains, and probiotic-associated bacteraemia risk exists in immunocompromised patients. Standard recurrent CDI therapy: fidaxomicin, faecal microbiota therapy, bezlotoxumab.

Sources

ICD-10: A04.7 · ICD-11: 1A04

Atopic dermatitis prevention in children

Individual decision

2015 gives a conditional recommendation in favour of probiotics in pregnant women with allergic history and their newborn infants for atopic dermatitis prevention. The effect is modest – about 10% absolute risk reduction. Most international allergy societies (, ) do not include probiotics in atopy prevention standards. Effects on food allergy or asthma prevention are not proven.

Sources

WAO: World Allergy Organization-McMaster University Guidelines for Allergic Disease Prevention: Probiotics (2015)

ICD-10: L20 · ICD-11: EA80

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Acne vulgaris (adjunctive therapy)

Not recommended

Probiotics (Lactobacillus, Bifidobacterium, Saccharomyces boulardii) are sold as a supplement that supposedly helps acne by shifting the gut microbiome. Studies have not shown a clear benefit for acne, and there is no solid evidence base for this use. Acne responds to other things instead: topical retinoids and benzoyl peroxide, with a doctor adding systemic treatment for moderate to severe cases. Do not take probiotics in place of treatment that does work, or you may miss the care you actually need

Sources

AGA: AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders (2020)

ICD-10: L70.0 · ICD-11: ED80

Major depressive disorder

Not recommended

Probiotics are live microorganisms (Lactobacillus, Bifidobacterium, the yeast Saccharomyces boulardii) taken for gut health. Riding the interest in the gut–brain axis, they are also promoted for mood and marketed as a supplement for depression. So far probiotics have not shown convincing benefit in depressive disorder: there is no evidence base for this use. What works for depression is psychotherapy and antidepressants, with the plan chosen by a doctor.

Sources

AGA: AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders (2020)

ICD-10: F32.9 · ICD-11: 6A70.Z

Prophylaxis of acute respiratory infections

Not recommended

Probiotics are live cultures of Lactobacillus, Bifidobacterium and the yeast Saccharomyces boulardii. They are promoted as a way to strengthen immunity and catch fewer colds. So far they have not shown convincing benefit for preventing acute respiratory infections, and there is no reliable evidence for this use. What actually helps against respiratory infections is vaccination (including flu shots), hand washing and good ventilation.

Sources

AGA: AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders (2020)

ICD-10: J06.9 · ICD-11: CA07.0

“Gut dysbiosis” as a standalone clinical diagnosis

Not recommended

«Gut dysbiosis» as a standalone diagnosis is absent from the international classification of diseases. , , , and WGO do not recognise it as a clinical entity and do not recommend «treating dysbiosis» with probiotics. In Russian practice the diagnosis is made by two methods, both problematic. First is stool culture, which does not reflect actual gut microbiota because 99 % of intestinal bacteria are strict anaerobes that do not grow on culture media. Second is the Osipov test (chromatography-mass spectrometry of microbial markers). The Russian Academy of Sciences in Memorandum No. 22 (2020) explicitly called this method pseudoscientific. Prescribing probiotics for a diagnosis that is not in the ICD, based on a test that the Academy considers pseudoscientific, has no evidence base.

Sources

AGA: AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders (2020)

Autism spectrum disorder

Not recommended

Probiotics for autism spectrum disorder have no evidence base. The 2018 Cochrane review (Parracho HM et al.) and 2021–2023 updates showed no convincing effect on core ASD symptoms. The American Academy of Pediatrics and AACAP do not include probiotics in their recommendations. Core ASD interventions: behavioural therapy, communication programs, early intervention. Positioning probiotics as «autism treatment» in post-Soviet marketing is particularly dangerous because it distracts families from evidence-based interventions and financially exploits parents in difficult circumstances.

Sources

AGA: AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders (2020)

ICD-10: F84 · ICD-11: 6A02

Weight loss

Not recommended

International guidelines do not include probiotics for weight loss. Systematic reviews (John GK et al. Genes 2018) showed an absolute weight reduction of 0.6 kg over 12 weeks, clinically insignificant. Endocrine Society, ACP, and AACE do not mention probiotics in obesity management. The «microbiome and weight» marketing relies on observational associations between bacterial profiles and obesity, but causality has not been established.

Sources

AGA: AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders (2020)

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (FAO/ 2002 definition). Mechanisms: competition with pathogenic flora for receptors and nutrients, short-chain fatty acid production, modulation of gut-associated lymphoid tissue immune responses, and epithelial barrier reinforcement. Effects are strain-specific: data on one Lactobacillus rhamnosus GG strain do not generalise to L. rhamnosus as a class.

Safety

Contraindications

Severe immunodeficiency (haematological malignancies, advanced HIV/AIDS, severe neutropenia)
Central venous catheters
Severe acute pancreatitis (per PROPATRIA RCT – increased mortality)
Hypersensitivity to components

Serious adverse effects

Probiotic-associated bacteraemia (Lactobacillus, Bifidobacterium) in immunocompromised patients
Fungaemia (Saccharomyces boulardii) in patients with central venous catheters
Endocarditis in patients with prosthetic heart valves (case reports)

Common adverse effects

Flatulence, abdominal discomfort in the first days
Mild diarrhoea or constipation (adaptive response)

Uncommon adverse effects

Allergic reactions
Skin rash

Pregnancy: can you take Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii)?

Safe in standard doses during pregnancy. Use for atopic dermatitis prevention in newborns from allergy-predisposed families is discussed with a clinician.

Breastfeeding: can you take Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii)?

Safe during breastfeeding. Do not transfer systemically from the maternal GI tract.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Probiotics for antibiotic-associated diarrhoea prevention are started **on day 1 of antibiotic therapy**, not after its completion. This is the 2020 and Cochrane 2019 position: the effect is achieved when probiotics are taken in parallel with antibiotics. Postponing intake until «after the course» is pointless – the risk is already realised by then. Within the day, the probiotic capsule and antibiotic dose are separated by about 2 hours so that the antibiotic does not destroy probiotic bacteria in the gut at once. Continue the course for 1–2 weeks after antibiotic completion. Saccharomyces boulardii is a yeast – antibacterial drugs do not affect it; time separation is unnecessary.

Dose titration

Dose for prevention in children: 5–10 billion CFU daily. In adults: 10–20 billion CFU daily. Dose is measured in CFU (colony-forming units), not preparation mass. Compare products by strain identity and CFU dose, not by “bacteria count” in grams. Duration: throughout the antibiotic course plus 1–2 weeks.

Monitoring

No specific monitoring at standard doses. In immunocompromised patients (cancer, HIV, organ transplantation, severe neutropenia, central venous catheters), there is a risk of probiotic-associated bacteraemia and fungaemia. In this group, probiotic use is discussed with the treating clinician.

Food and drinks

Dietary probiotic sources: fermented dairy (live-culture yoghurt, kefir, ryazhenka), sauerkraut, kimchi, kombucha. CFU content in foods is lower than in preparations – ordinary yoghurt contains 100 million – 1 billion CFU per serving, 10 times less than the therapeutic dose.

Common myths

In post-Soviet medical practice probiotics are prescribed for a wide range of conditions without international evidence. Common misconceptions include the following.

Myth: «I have dysbiosis, so I need a probiotic course». Fact: «gut dysbiosis» as a standalone clinical diagnosis is absent from ICD-10 and ICD-11. , , , WGO do not recognise it. In Russian practice the diagnosis is made via stool culture – which does not reflect actual gut microbiota because 99 % of gut bacteria are strict anaerobes and do not grow on culture media. Or via the Osipov test (chromatography-mass spectrometry of microbial markers). The Russian Academy of Sciences in Memorandum No. 22 (2020) explicitly called this method pseudoscientific. «Treating dysbiosis» means treating a diagnosis that does not exist based on a test that does not work.

Myth: «the Osipov test showed which bacteria are missing, so I should supplement them via probiotics». Fact: the Osipov methodology is not recognised by the international scientific community. The 2020 Memorandum No. 22 of the Russian Academy of Sciences Commission Against Pseudoscience explicitly classifies the method as pseudoscientific. Test results lack clinical interpretation. If a clinician builds treatment on Osipov test results, a second opinion is warranted.

Myth: «probiotics restore microbiota after antibiotics». Fact: native microbiota recovers over 2–8 weeks regardless of probiotic intake. Probiotics reduce antibiotic-associated diarrhoea risk but do not restore microbiota composition. The 2018 Cochrane review showed no recovery effect in adults.

Myth: «probiotics treat acne through the gut-skin axis». Fact: Acne Guidelines 2024 and EDF 2024 do not recommend probiotics in acne. Clinical evidence is absent. Standard acne therapy: topical retinoids, benzoyl peroxide, systemic antibiotics, or isotretinoin when needed.

Myth: «probiotics aid weight loss». Fact: systematic reviews showed weight reduction of 0.6 kg over 12 weeks – clinically insignificant. Endocrine Society and other obesity societies do not include probiotics in recommendations.

Myth: «psychobiotics treat depression and anxiety». Fact: , Mental Health, and WFSBP do not include probiotics in depression or anxiety recommendations. The «gut-brain axis» marketing outpaces clinical evidence.

Myth: «probiotics improve the condition of children with autism». Fact: Cochrane 2018 and 2021–2023 updates did not show convincing effects on ASD symptoms. and AACAP do not support the practice. Positioning probiotics as «autism treatment» is financial exploitation of families and distraction from evidence-based interventions (behavioural therapy, early intervention).

Myth: «more strains in the bottle means better effect». Fact: effects are strain-specific. «Multi-strain complexes of 15 cultures» are marketing. Clinical RCTs tested specific strains: Lactobacillus rhamnosus GG, Saccharomyces boulardii, Bifidobacterium infantis 35624. Data on one strain do not transfer to others.

Myth: «probiotics are absolutely safe for everyone». Fact: in immunocompromised patients and people with central venous catheters there is a risk of bacteraemia and fungaemia. In severe acute pancreatitis, the multicentre PROPATRIA RCT 2008 showed increased mortality with probiotic use.

Check interaction with another drug

Opens the checker prefilled with this drug. Pick the second one from your regimen.

Open checker

Summary of a multi-drug list →

Medicine list: everything you take in one place →

Frequently asked

What is Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii) used for?

Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii) is evaluated for the following indications with varying evidence strength: Antibiotic-associated diarrhoea (evidence tier B), Prevention of Clostridioides difficile infection recurrence (evidence tier C), Irritable bowel syndrome (evidence tier C). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii)?

Common side effects of Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii) (≥ 1 in 100): Flatulence, abdominal discomfort in the first days, Mild diarrhoea or constipation (adaptive response). See the Safety section for uncommon and serious reactions.

Is Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii) safe during pregnancy?

Safe in standard doses during pregnancy. Use for atopic dermatitis prevention in newborns from allergy-predisposed families is discussed with a clinician.

Is Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii) compatible with breastfeeding?

Safe during breastfeeding. Do not transfer systemically from the maternal GI tract.

Who should not take Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii)?

Probiotics (Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii) is contraindicated in: Severe immunodeficiency (haematological malignancies, advanced HIV/AIDS, severe neutropenia); Central venous catheters; Severe acute pancreatitis (per PROPATRIA RCT – increased mortality); Hypersensitivity to components. Full list in the Safety section.

I have dysbiosis, so I need a probiotic course

«gut dysbiosis» as a standalone clinical diagnosis is absent from ICD-10 and ICD-11. AGA, ACG, BSG, WGO do not recognise it. In Russian practice the diagnosis is made via stool culture – which does not reflect actual gut microbiota because 99 % of gut bacteria are strict anaerobes and do not grow on culture media. Or via the Osipov test (chromatography-mass spectrometry of microbial markers). The Russian Academy of Sciences in Memorandum No. 22 (2020) explicitly called this method pseudoscientific. «Treating dysbiosis» means treating a diagnosis that does not exist based on a test that does not work.

the Osipov test showed which bacteria are missing, so I should supplement them via probiotics

the Osipov methodology is not recognised by the international scientific community. The 2020 Memorandum No. 22 of the Russian Academy of Sciences Commission Against Pseudoscience explicitly classifies the method as pseudoscientific. Test results lack clinical interpretation. If a clinician builds treatment on Osipov test results, a second opinion is warranted.

probiotics restore microbiota after antibiotics

native microbiota recovers over 2–8 weeks regardless of probiotic intake. Probiotics reduce antibiotic-associated diarrhoea risk but do not restore microbiota composition. The 2018 Cochrane review showed no recovery effect in adults.

probiotics treat acne through the gut-skin axis

AAD Acne Guidelines 2024 and EDF 2024 do not recommend probiotics in acne. Clinical evidence is absent. Standard acne therapy: topical retinoids, benzoyl peroxide, systemic antibiotics, or isotretinoin when needed.

probiotics aid weight loss

systematic reviews showed weight reduction of 0.6 kg over 12 weeks – clinically insignificant. Endocrine Society and other obesity societies do not include probiotics in recommendations.

psychobiotics treat depression and anxiety

APA, NICE Mental Health, and WFSBP do not include probiotics in depression or anxiety recommendations. The «gut-brain axis» marketing outpaces clinical evidence.

probiotics improve the condition of children with autism

Cochrane 2018 and 2021–2023 updates did not show convincing effects on ASD symptoms. AAP and AACAP do not support the practice. Positioning probiotics as «autism treatment» is financial exploitation of families and distraction from evidence-based interventions (behavioural therapy, early intervention).

more strains in the bottle means better effect

effects are strain-specific. «Multi-strain complexes of 15 cultures» are marketing. Clinical RCTs tested specific strains: Lactobacillus rhamnosus GG, Saccharomyces boulardii, Bifidobacterium infantis 35624. Data on one strain do not transfer to others.

probiotics are absolutely safe for everyone

in immunocompromised patients and people with central venous catheters there is a risk of bacteraemia and fungaemia. In severe acute pancreatitis, the multicentre PROPATRIA RCT 2008 showed increased mortality with probiotic use.

Other drugs in this group

Saccharomyces boulardii CNCM I-745, Sulfasalazine, Berberine, Bifidobacterium longum, Lactobacillus rhamnosus GG (LGG), Mesalazine, Curcumin (Curcuma longa extract), Diosmectite