Probiotika sind in einer kurzen Liste von Situationen hilfreich. Der klarste Anwendungsfall ist eine Antibiotikatherapie: Die genannten Stämme Lactobacillus rhamnosus GG und die Hefe Saccharomyces boulardii reduzieren die Durchfälle, die Antibiotika häufig verursachen. Bei dem Reizdarmsyndrom bieten sie eine moderate Unterstützung. Die Produktkategorie wird jedoch mit einem viel größeren Versprechen vermarktet – dass jeder täglich ein Probiotikum zur allgemeinen Darmgesundheit einnehmen sollte.
Hier wird der wissenschaftliche Nachweis dünner. Für die meisten Menschen decken fermentierte Lebensmittel den allgemeinen Bedarf ab, und die Studiennachweise für Nahrungsergänzungsmittel beschränken sich auf einige spezifische Situationen. Bestimmte Gruppen, vor allem immungeschwächte und schwerstkranke Patienten, sollten bei der Einnahme von Präparaten mit lebenden Organismen vorsichtig sein.
Findings & Outcomes
What It Is
A probiotic is a live bacterium or yeast taken by mouth to do a job inside the digestive tract.
Anatomy of the Practice
1A live organism that passes through
It travels through the digestive tract without settling in: most strains never colonize. A probiotic acts while it passes through and while you keep taking it. This is why any effect fades once you stop. It is also why the specific strain and dose matter more than the word probiotic on the front.
2During a course of antibiotics
Antibiotics clear out resident gut bacteria along with the infection. That emptied space is where antibiotic-associated diarrhea and, less often, a Clostridioides difficile overgrowth take hold. A probiotic taken during the course competes for that space and limits how far those organisms grow. Saccharomyces boulardii is a common choice for this window.
3In an already healthy gut
In a person who is already well, the resident microbiome is a stable community with its own set point. A supplement nudges it only while the doses keep coming, and it settles back once they stop.
What It Does
On antibiotics, a probiotic taken alongside the drug prevented about one case of diarrhea for every 13 people treated. The two organisms with the firmest single-strain support are the yeast Saccharomyces boulardii and the bacterium Lactobacillus rhamnosus GG. Taken with antibiotics, a probiotic also lowers Clostridioides difficile diarrhea, a serious gut infection. That protection is largest for people already at high risk, such as older hospitalized patients on broad-spectrum antibiotics.
Irritable bowel syndrome is next: the pooled benefit is modest and depends on the strain. Beyond these specific jobs, the evidence is weak. In a well person, the same daily capsule leaves the resident gut community unchanged over time. In nearly 1,900 children with an ordinary stomach bug, a probiotic worked no better than placebo for the diarrhea itself.
In a trial of critically ill patients with severe pancreatitis, a probiotic mixture was linked to more deaths and did not reduce infections.
The Research & Studies
Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.
Digestion
In two large trials, probiotics were no better than placebo for children’s acute diarrhea (RR 0.96)
For a child with an ordinary stomach bug and diarrhea, two large, careful trials found that a five-day probiotic course worked no better than a placebo. This is one of the clearest examples of a probiotic use that sounds obvious and did not hold up.
Two large randomized, placebo-controlled trials published together in the New England Journal of Medicine tested probiotics for acute gastroenteritis in children. Schnadower 2018 gave Lactobacillus rhamnosus GG (10 billion colony-forming units twice daily for 5 days) to 971 children and found moderate-to-severe gastroenteritis within 14 days in 11.8% versus 12.6% on placebo, relative risk 0.96 (95% CI 0.68 to 1.35, P=0.83). Freedman 2018 gave a combination of L. rhamnosus R0011 and L. helveticus R0052 to 886 children and found moderate-to-severe gastroenteritis in 26.1% versus 24.7% on placebo, odds ratio 1.06 (95% CI 0.77 to 1.46, P=0.72). Neither improved duration of diarrhea or vomiting. Both concluded the probiotic did not help.
The studies · 2
Schnadower 2018, N Engl J Med (L. rhamnosus GG) · N Engl J Med
Freedman 2018, N Engl J Med (combination probiotic) · N Engl J Med
Probiotics with antibiotics prevent one case of diarrhea for every 13 people treated
Taking a probiotic alongside a course of antibiotics lowers the chance of the loose stools antibiotics often cause. Across a large body of trials it prevented about one case for every 13 people who took one.
A systematic review and meta-analysis of 63 randomized controlled trials in 11,811 participants (Hempel 2012, JAMA) found probiotics reduced the risk of antibiotic-associated diarrhea versus control, pooled relative risk 0.58 (95% CI 0.50 to 0.68), risk difference -0.07 (95% CI -0.10 to -0.05), number needed to treat 13 (95% CI 10.3 to 19.1). The trials pooled many different organisms and doses, so the estimate is an average across a heterogeneous literature, not a result for one product; the review noted the evidence did not let it say which strain was best.
The study · 1
Hempel 2012, JAMA · JAMA
Saccharomyces boulardii cut antibiotic diarrhea from about 19 to about 9 in 100
Saccharomyces boulardii, a probiotic yeast, roughly halved antibiotic-associated diarrhea in the trials that tested it, dropping it from about 19 in 100 people to about 9 in 100.
A systematic review with meta-analysis of 21 randomized controlled trials in 4,780 participants (Szajewska 2015, Aliment Pharmacol Ther) found Saccharomyces boulardii reduced the risk of antibiotic-associated diarrhea from 18.7% in controls to 8.5%, relative risk 0.47 (95% CI 0.38 to 0.57). S. boulardii is a yeast, so ordinary antibacterial antibiotics do not kill it, which is one reason it is a common choice during an antibiotic course. This is a strain-specific result, not a claim about probiotics in general.
The study · 1
Szajewska 2015, Aliment Pharmacol Ther (S. boulardii) · Aliment Pharmacol Ther
Lactobacillus rhamnosus GG cut antibiotic diarrhea from about 22 to about 12 in 100
Lactobacillus rhamnosus GG, one of the most studied single strains, roughly halved antibiotic-associated diarrhea, from about 22 in 100 people to about 12 in 100.
A systematic review with meta-analysis of 12 randomized controlled trials in 1,499 participants (Szajewska 2015, Aliment Pharmacol Ther) found Lactobacillus rhamnosus GG reduced antibiotic-associated diarrhea from 22.4% in controls to 12.3%, relative risk 0.49 (95% confidence interval 0.29 to 0.83). Like the S. boulardii result, this is tied to one named strain; it is the reason S. boulardii and L. rhamnosus GG are the two organisms most often named for this specific job.
The study · 1
Szajewska 2015, Aliment Pharmacol Ther (L. rhamnosus GG) · Aliment Pharmacol Ther
In children on antibiotics, probiotics cut diarrhea from about 19 to about 8 in 100
In children taking antibiotics, a probiotic cut the rate of diarrhea from about 19 in 100 to about 8 in 100, and the higher-dose products worked better than low-dose ones.
A Cochrane systematic review and meta-analysis of 23 studies in 3,938 children (Goldenberg 2015) found probiotics reduced antibiotic-associated diarrhea from 19% (364 of 1,906) in controls to 8% (163 of 1,992), relative risk 0.46 (95% CI 0.35 to 0.61). A dose subgroup analysis favored higher doses (5 billion or more colony-forming units per day). The best-supported organisms in the pediatric trials were, again, Lactobacillus rhamnosus GG and Saccharomyces boulardii.
The study · 1
Goldenberg 2015, Cochrane Database Syst Rev (pediatric AAD) · Cochrane Database Syst Rev
Probiotics with antibiotics cut C. difficile diarrhea from about 4 to about 1.5 in 100
Given alongside antibiotics, a probiotic lowered the rate of C. difficile diarrhea, a serious gut infection, from about 4 in 100 to about 1.5 in 100. The benefit was largest in people whose baseline risk was already high.
A Cochrane review and meta-analysis of 31 trials in 8,672 people (Goldenberg 2017) found probiotics, taken with antibiotics, reduced Clostridioides difficile-associated diarrhea from 4.0% (164 of 4,147) in controls to 1.5% (70 of 4,525), relative risk 0.40 (95% CI 0.30 to 0.52), number needed to treat 42. In the subgroup at high baseline risk (control-group rate above 5%) the effect was larger, relative risk 0.30 (95% CI 0.21 to 0.42), number needed to treat 12. Where baseline risk was low, the absolute benefit was small.
The value is greatest during a high-risk antibiotic course, for example an older hospitalized person on broad-spectrum antibiotics, and smaller for a young healthy person on a short outpatient course.
The study · 1
Goldenberg 2017, Cochrane Database Syst Rev (C. difficile) · Cochrane Database Syst Rev
Probiotics give modest relief in irritable bowel syndrome (RR 0.79 versus placebo)
For irritable bowel syndrome, probiotics helped somewhat more people feel better than placebo did, with improvements in abdominal pain, bloating and wind. The effect is modest and it is not clear which product to reach for.
A systematic review and meta-analysis (Ford 2014, Am J Gastroenterol) pooled 43 randomized controlled trials and found the relative risk of IBS symptoms persisting was 0.79 (95% CI 0.70 to 0.89) with probiotics versus placebo, with benefit seen for global IBS symptoms, abdominal pain, bloating and flatulence. The authors concluded probiotics are effective for IBS but that which individual species and strains are most beneficial remains unclear. The effect is modest, and the uncertainty about strain is the practical limit.
The study · 1
Ford 2014, Am J Gastroenterol · Am J Gastroenterol
Whether probiotics help irritable bowel depends on the strain: 7 of 11 recent trials improved symptoms
Whether a probiotic helps IBS depends heavily on which one it is. In a set of recent trials, roughly two-thirds improved symptoms and a third did nothing, with multi-strain products taken for at least eight weeks looking best.
A systematic review (Dale 2019, Nutrients) of 11 recent randomized controlled trials found that 7 (63.6%) reported a significant improvement in IBS symptoms versus placebo while the remainder did not, and that effects were more distinct in trials using multi-strain supplements for 8 weeks or longer. Across these trials the results split: probiotics for IBS depend on the strain and the duration, which is why the pooled benefit holds even though the direction for any one product is mixed.
If trying one for IBS, give a multi-strain product a fair run of at least eight weeks, and if it has done nothing by then, stop, not keep paying for it.
The study · 1
Dale 2019, Nutrients (IBS systematic review) · Nutrients
In healthy adults, probiotics did not lastingly change gut bacteria or blood lipids
The idea that a healthy person should take a daily probiotic to improve general gut health is not backed by the research. In healthy adults, probiotics did not lastingly change the gut bacteria, and the general-wellness benefits are inconsistent.
A systematic review of probiotic supplementation in healthy adults (Khalesi 2019, Eur J Clin Nutr) found some short-term signals in immune, gastrointestinal and female reproductive measures, but concluded that the evidence did not support probiotics causing persistent changes in the gut microbiota or improving blood lipid profiles in healthy adults. In healthy people the resident microbiome tends to return to its own set point once supplementation stops. The established benefits of probiotics are specific strain-and-condition pairings, not a general daily tonic for people who are already well.
The study · 1
Khalesi 2019, Eur J Clin Nutr (healthy adults review) · Eur J Clin Nutr
How It Works
A probiotic works by crowding. In large enough numbers, a strain competes with resident gut organisms for space and food. It shifts the local chemistry and touches the gut lining and its immune tissue while passing through. The effect is local, and it lasts only while the doses keep coming. Few strains take up residence, so the benefit fades once you stop and the gut returns to its baseline. This is also why the evidence attaches to the specific named strain: a result for one organism in one job does not transfer to another. All 63 trials behind the antibiotic benefit (11,811 people) tested a gut with room to fill after antibiotics. A settled healthy gut has no such room.
Getting It Right
Ways to Do It
Match the probiotic to a specific job. The trial support sits in particular situations; the everyday case is covered by fermented foods within a whole diet.
For the general case, put fermented foods first. Live-culture yogurt, kefir, sauerkraut, kimchi, miso, and tempeh deliver a changing mix of organisms inside a whole diet. They bring fiber and other nutrients a single-strain capsule does not. See [whole foods](/go/integrative/practice/whole-foods) for the same principle across the diet.
When there is a specific job to do, the strain is the decision. For diarrhea during a course of antibiotics, the two organisms with the strongest trial support are Saccharomyces boulardii and Lactobacillus rhamnosus GG. Higher-dose products worked better in the pediatric trials. For irritable bowel syndrome, the better trials ran a multi-strain product for at least eight weeks. Read the label for the exact species and strain. Products labeled only probiotic can hold any organism, with any evidence behind it or none.
The trial evidence does not support a probiotic for a healthy person seeking general gut health, or for a child with an ordinary viral stomach bug. Fermented food covers the general case; a named strain has support only for the specific jobs it was tested on.
Go Deeper
- Whole foods: the diet that puts fermented foods and fiber to everyday use.
- Fiber: the food that feeds the resident gut bacteria.
- Type 2 diabetes: a condition where gut and metabolic claims for probiotics are made freely, held to the same per-claim standard as everything else.
The Chinese Medicine View
The capsule of isolated cultured strains is a 20th-century product with no classical entry, so the tradition speaks to it only by analogy. In Chinese medicine digestion belongs to the Spleen and Stomach, the pair that receives food and transforms it into the substances the body runs on. When that transforming function is weak, the result is loose stools, bloating, fatigue, and a heavy feeling, the same territory these products are marketed toward.
The tradition has its own fermented remedies. Shen Qu, a fermented cake of wheat flour and herbs, moves food stagnation and supports digestion. Dan Dou Chi, a fermented soybean, is a long-standing materia medica item.
The tradition also matches the food to the person. The Spleen dislikes damp, and some dairy-based fermented foods are damp-forming. A practitioner fits those to the person's constitution, easing off for someone who already tends damp.
Cautions For This Practice
Extra restraintEverything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.
For healthy people, probiotics are generally safe, with mild gas or bloating at first
A review of the risk and safety of probiotics (Doron 2015, Clin Infect Dis) concluded that probiotics are generally safe for most people, with the most common adverse effects being mild and gastrointestinal, such as gas and bloating. For the general, healthy population the safety record across a large trial literature is reassuring. The serious risks that do exist are concentrated in specific vulnerable groups, which is a separate matter covered below.Doron 2015, Clin Infect Dis (risk and safety of probiotics)
In immunocompromised or critically ill people, probiotics can cause bloodstream infection
A review of probiotic risk and safety (Doron 2015, Clin Infect Dis) describes that the principal serious hazard of live probiotics is systemic infection, when the organism moves from the gut into the bloodstream, alongside deleterious metabolic activity, excessive immune stimulation in susceptible people, and gene transfer. These events are rare overall but are concentrated in vulnerable groups: people with weakened immune systems, critical illness, or an indwelling central venous catheter. Both bacterial bloodstream infection and yeast fungemia have been reported in such patients. For these groups, a probiotic is a medical decision, not a self-care one.Doron 2015, Clin Infect Dis (risk and safety of probiotics)
In severe acute pancreatitis, a probiotic mixture raised deaths to 16 in 100 versus 6
A randomized, double-blind, placebo-controlled trial (Besselink 2008, Lancet) gave a multispecies probiotic preparation or placebo to 298 patients with predicted severe acute pancreatitis. The probiotic did not reduce infectious complications and was associated with increased mortality: 24 of 152 patients (16%) in the probiotic group died compared with 9 of 144 (6%) on placebo. The authors concluded that probiotic prophylaxis should not be given to this category of patients. It stands as direct trial evidence that live probiotics can cause harm in the critically ill, not only in theory.Besselink 2008, Lancet (PROPATRIA trial)
The immunocompromised, the critically ill, and central lines
In a person whose immune defenses are down, who is seriously unwell, or who has a central venous catheter, live probiotic organisms can cross into the bloodstream. There they cause a systemic infection, and both bacterial infection and yeast fungemia have been reported. In a trial of critically ill patients with severe pancreatitis, a probiotic mixture was linked to more deaths and did not reduce infections. If you or someone you care for is in one of these groups, treat a probiotic as a medical decision to make with a clinician.
What is on the label may not be in the bottle
Probiotic supplements are loosely regulated, and the live-organism count printed on the label often does not survive shipping, shelf time, and stomach acid. Look for a product that names the organism to the strain level, and states the dose in colony-forming units guaranteed through the end of shelf life. Store it as the label directs; many strains need refrigeration to stay alive.
Timing around the antibiotic dose
If you are taking a bacterial probiotic during an antibiotic course, separating the two by about two hours keeps the antibiotic from killing the strains you just took. This does not apply to Saccharomyces boulardii. It is a yeast, so antibacterial antibiotics do not touch it, and it can be taken at any time.
Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.
Common Questions
Do probiotics help while I am taking antibiotics?
Yes, for the diarrhea. A probiotic does not treat the infection the antibiotic targets; it competes for the gut space the drug empties, which is what lowers the loose stools.
How long until a probiotic does anything, and do the effects last?
Two timelines, depending on the job. For the antibiotic use it works across the course itself, over days. For irritable bowel syndrome, judge it only after a couple of months; a few doses prove nothing. It is not a one-time fix: keep taking it for as long as the problem it targets is present.
Explore Related
Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.
All 13 sources on this page independently checked and cross-referenced.
Thomas Dehli, Founder & Editor, Sacred Lotus
Sacred Lotus has published Chinese medicine reference material since 2001. Integrative pages are held to the same standard as the herb and formula library: cite the source, grade the claim at its real strength, and say where the research has not looked. This page is educational and it is not medical advice. Last reviewed and updated August 9, 2026.
Evidence strength
How confidently the research supports a claim. Strength describes the evidence, not our endorsement.