Probiotics for Acid Reflux: What the Small Studies Show

Probiotics for acid reflux are not a proven treatment, but a few specific strains have eased reflux symptoms in small studies. The main systematic review found that 11 of 14 study comparisons reported some upper-gut benefit, yet only 5 touched heartburn or regurgitation, and 6 of the 13 studies were low quality^[1]. A U.S. health agency calls the research on probiotics for reflux "limited"^[2].

This guide covers what those trials actually tested, which strains were used and at what doses, how probiotics fit with PPIs, what the stomach bacterium H. pylori has to do with reflux, and when a probiotic is the wrong tool.

Get medical help promptly if heartburn comes with trouble or pain when swallowing, vomit that contains blood or looks like coffee grounds, black and tarry stools, unexplained weight loss, loss of appetite, persistent vomiting, or chest pain^[3]. These can signal bleeding, a complication of GERD or another serious problem, and need a clinician, not a supplement.

Do probiotics actually help acid reflux symptoms?

Sometimes, a little, for some symptoms. The best summary is a 2020 systematic review of 13 prospective studies with 951 participants, mostly healthy adults who were not taking reflux medicine. Most positive results were for indigestion, belching and stomach discomfort rather than for classic heartburn^[1].

Three cautions apply. The 13 studies tested eight different products in very different formats, and the review did not pool them into one estimate. Only five were rated high quality, and the authors called for larger placebo-controlled trials before drawing firm conclusions^[1]. And a later meta-analysis of diet, supplement and probiotic approaches to GERD symptoms included only three probiotic interventions, and a single probiotic yogurt study showed clear improvement^[4].

So, can probiotics help acid reflux? They may ease regurgitation, burping or post-meal fullness in some people. They are not a substitute for treatment of GERD and the gut microbiome changes that come with it.

How could probiotics affect reflux?

Probiotics are not antacids, and the reflux trials did not test them as acid reducers. Reflux mostly happens because the lower esophageal sphincter, the valve between the esophagus and stomach, is weak or relaxes when it shouldn't, sometimes with a hiatal hernia^[3]. No probiotic changes that anatomy.

The proposed mechanisms are indirect:

• Faster stomach emptying. Some probiotics may speed gastric emptying through receptors in the stomach lining, a pathway reviewers link to transient relaxations of the valve, one of the main mechanisms of GERD^[1].
• Digestion and stomach signals. In one study of Lactobacillus gasseri LG21, reflux scores were linked to blood levels of pepsinogen I, the precursor of a protein-digesting enzyme^[1].
• Gut microbiome shifts during PPI treatment. In two recent trials, people given a probiotic alongside a PPI had more gut Bifidobacterium than people on a PPI alone^[5][6]. One also found higher levels of GABA and short-chain fatty acids, compounds gut bacteria make when they ferment fiber^[6]. Whether those shifts cause the symptom changes is not known.

The overlap with indigestion matters too. Reflux, heartburn and dyspepsia are hard to tell apart, the review did not separate them, and the strains with the most data were tested mainly for stomach symptoms^[1].

Which probiotic strains have been tested for reflux?

A handful, mostly in Japan and China, and usually in one or two trials each. Benefits are strain-specific: the code after the species name matters, because a different strain of the same species may do nothing^[7].

Several of these trials had authors from food or pharmaceutical companies, including the L. gasseri, L. johnsonii and multi-strain studies^[8][10][6]. The L. acidophilus product also contained other active ingredients, so its effect cannot be credited to the bacteria alone^[9].

Is there a best probiotic for acid reflux?

No single strain has been tested enough to be called the best probiotic for acid reflux or GERD. L. gasseri LG21 has the most consistent data, with all three of its studies reporting some benefit, followed by B. bifidum YIT 10347^[1].

Both were studied as dairy foods, not capsules. A supplement that lists only "Lactobacillus acidophilus" without a strain code is not the product that was tested.

A retracted trial that still circulates

You may see a 2019 trial of Bacillus subtilis and Enterococcus faecium with esomeprazole cited as proof that probiotics prevent reflux relapse. Its authors retracted it in 2023 because a research assistant mixed up the two treatments when dispensing them, so patients' labels may not match what they actually took^[12]. We have left its results out of this article.

Can you take probiotics with PPIs and other reflux medicine?

Probiotics can be combined with a PPI, and that is how the newer trials tested them; check with your doctor or pharmacist first. Proton pump inhibitors (PPIs) reduce stomach acid and heal the esophagus in most people with GERD; they are generally safe, though they may raise the chance of C. difficile infection^[13]. A meta-analysis of 19 studies (7,055 people) also linked PPI use to a moderately higher risk of small intestinal bacterial overgrowth (SIBO), with an odds ratio of 1.71^[14].

The add-on trials suggest three things:

1. Adding B. animalis subsp. lactis MH-02 to a PPI shortened the time to symptom relief and delayed relapse after treatment^[5].
2. A multi-strain probiotic kept reflux scores lower after the PPI stopped, but did not significantly improve healing of the esophagus (36.8% vs 12.5%)^[6].
3. In children on PPIs, L. reuteri DSM 17938 cut bacterial overgrowth from 56% to 6%^[11].

We found no trial that tested probiotics alongside antacids or H2 blockers; the add-on studies all used PPIs. Never stop or taper a prescribed PPI to try a probiotic instead. Our article on how PPIs change gut bacteria covers the microbiome side effects in detail.

What does H. pylori have to do with reflux?

H. pylori is the bacterium that infects the stomach lining, and its relationship with reflux is the opposite of what many people expect. A recent meta-analysis cited in the Maastricht VI consensus found a weak link between H. pylori infection and fewer reflux symptoms^[15]. The same expert panel concluded that the old claim that curing H. pylori causes meaningful damage to the esophagus was never based on consistent findings^[15].

Probiotics do not eradicate H. pylori, although they have been shown to reduce its activity^[1]. Their role is supporting antibiotic treatment:

• Certain probiotics, including some Lactobacilli and the yeast Saccharomyces boulardii, reduce the gut side effects of eradication therapy (consensus grade A2)^[15].
• An umbrella review of 28 meta-analyses found probiotics alongside standard therapy were linked to slightly higher cure rates (RR 1.10) and fewer side effects (RR 0.54), though most of the analyses were of low quality^[16].
• The panel judged that any rise in cure rates comes from reducing the antibiotics' side effects, not from a direct effect on the bacterium^[15].

Two practical points follow.

None of the reflux probiotic trials recorded whether participants carried H. pylori, which makes their results harder to interpret^[1]. And L. gasseri LG21 still helped indigestion in people without the infection^[8]. Our article on whether H. pylori is contagious explains how the infection spreads and who is at risk.

Can probiotics make acid reflux worse?

Rarely, in the trials. Nine of the studies in the 2020 review recorded side effects, and none differed from placebo; there were no serious adverse events^[1]. One small study did see a slight rise in a "dysmotility-like" indigestion score (3.5 to 4.0) while reflux scores fell^[1].

Safety concerns are greater outside healthy adults. Severe and fatal infections have been reported in premature infants given probiotics, and the risk of harm is higher in people who are seriously ill or immunocompromised^[7]. Some products have also been found to contain microbes not listed on the label^[7]. If a new probiotic brings on bloating or discomfort, our guide to probiotic side effects explains what is usually temporary and what is not.

Is yogurt or kefir good for acid reflux?

Much of the reflux research used yogurt or fermented milk, but only with specific strains. The L. gasseri LG21 and B. bifidum YIT 10347 results above came from yogurt and fermented milk^[1], and a probiotic yogurt was one of only a few dietary interventions to improve GERD symptoms in a 2022 meta-analysis^[4].

Kefir is a different case. When we searched the research literature for this article, we found no clinical trial of kefir for heartburn or reflux. Our kefir vs. yogurt comparison covers how the two differ in microbes.

How to try a probiotic for reflux sensibly

If your symptoms are mild and you have no red flags, a time-limited trial is reasonable:

1. Pick a strain that was studied. Look for the full strain name on the label, such as LG21, YIT 10347 or HN019, rather than a species alone^[1].
2. Use a studied amount. Trials used 0.05 to 46 billion CFU a day, with an average of about 6 billion^[1].
3. Give it 4 to 8 weeks. The trials ran 1 to 12 weeks, averaging 6^[1]. See how long probiotics take to work.
4. Keep a symptom diary. Note heartburn days, regurgitation and antacid use, the outcomes trials measured^[9].
5. Keep the measures that work. Losing weight if overweight, raising the head of the bed 6 to 8 inches, stopping smoking and adjusting meals are all recommended by NIDDK^[13].
6. Tell your clinician. NCCIH advises checking with your provider before adding any supplement to GERD care^[2].

Time of day matters less than consistency; our guide on when to take probiotics covers the evidence on timing.

Probiotics for reflux in babies and children

Spit-up is common in babies^[17], and a few trials suggest some probiotics reduce it. A 2021 meta-analysis of three trials found about 1.8 fewer regurgitation episodes a day with probiotics, but the studies were small and results varied widely^[17]. In the largest trial, 589 healthy newborns given L. reuteri DSM 17938 for 90 days had 2.9 regurgitations a day at 3 months, compared with 4.6 on placebo^[18].

Premature babies face a risk of severe, sometimes fatal infection from probiotics, and the FDA has warned clinicians about it^[7]. Talk to your pediatrician before using any product, and see our guide to probiotics for infants and newborns.

When to see a doctor

See a doctor rather than trying another supplement if:

• you have heartburn more than twice a week, which usually means GERD^[2]
• you have needed over-the-counter reflux medicine for more than 2 weeks^[2]
• your symptoms don't improve with medicine or lifestyle changes^[3]
• you have trouble or pain swallowing, persistent vomiting, or lose weight without trying^[3]
• you vomit blood or coffee-ground material, or pass black, tarry stools^[3]
• you have chest pain^[3]

Ongoing GERD can lead to a narrowed esophagus or Barrett's esophagus, and untreated GERD is a major risk factor for esophageal cancer^[2]. Our apple cider vinegar for reflux article looks at another popular home remedy and what the evidence shows.

This article is for general educational purposes and is not medical advice. It summarizes small trials of probiotics for reflux symptoms and does not replace an evaluation of your symptoms. Do not stop, start or change any reflux medicine without talking to a qualified healthcare professional, particularly if you are pregnant, immunocompromised, taking prescription medication, or managing a diagnosed condition such as GERD or Barrett's esophagus.