Can I Take Probiotics With Omeprazole? What the PPI Trials Found

Yes: nothing in the trial record shows that live cultures interfere with omeprazole or that omeprazole stops them working, and no trial reports a problem from taking the two together. The reason people ask is real: two large studies found that people on acid-suppressing medicines carry a less diverse gut community, with more bacteria of the kind found in the mouth.^{1, 2} This page is one spoke of the Wellgard probiotics guide.

Evidence at a glance

• Trials: two population cohorts (1,815 people; 1,827 twins) and two randomised trials (30 and 26 people).
• Largest trial: 30 healthy adults, six weeks, a proton-pump inhibitor or placebo plus a multi-strain culture.
• Strongest measured outcome: the culture reduced one bacterial shift the medicine caused (P = 0.01); no symptom was measured.
• Not tested: any symptom, infection or overgrowth outcome on omeprazole outside prescribed H. pylori treatment.

Sources checked on 12 October 2026.

So, can I take probiotics with omeprazole?

Yes. "Interfere" would mean omeprazole stopping the cultures reaching the lower gut alive, or the cultures changing how omeprazole works. No trial reports either; the one trial that measured survival found more of the culture's species in the stool when acid was suppressed, not fewer.³ The NHS omeprazole page, reviewed 17 September 2025, lists what "may not mix well with omeprazole", and live cultures are not on it; it asks you to tell a doctor or pharmacist about "any other medicines, herbal remedies, vitamins or supplements".⁴

Does omeprazole affect your gut bacteria?

Yes, measurably, in two 2016 studies. In 1,815 people, 211 of them taking a proton-pump inhibitor, users had lower bacterial diversity and differences in 20% of the bacterial groups measured, with mouth bacteria over-represented in their stool; the authors call it a shift "towards a less healthy gut microbiome", in line with changes known to go before Clostridioides difficile infection.¹ In 1,827 healthy twins, users again had lower diversity and more mouth and upper-gut bacteria, especially the Streptococcaceae family, including in 70 identical-twin pairs where only one twin took the medicine.²

Both are associations, not proof of harm, and neither abstract records the dose or years of use. The explanation both propose is that stomach acid is a gatekeeper; with less of it, bacteria swallowed from the mouth reach the lower gut in larger numbers.²

Can live cultures offset the effect omeprazole has on the gut?

Partly, in one small double-blind trial with no symptom measured: 30 healthy adults took a proton-pump inhibitor or placebo for six weeks, and everyone took a multi-strain live culture from week two to week six.³ The medicine raised three bacterial families; the culture reduced one of those shifts (Leuconostocaceae, P = 0.01); and with acid suppressed, more of the culture's species were found in the stool (P < 0.05).³ In a second double-blind trial, 26 adults with Helicobacter pylori took a proton-pump inhibitor with a high-dose Lactobacillus reuteri product or placebo: the species was found only at one month and the gut community was "returning to baseline shortly after therapy".⁵

The one upper-gut setting with pooled outcomes is prescribed H. pylori eradication, a course that includes a proton-pump inhibitor: across 91 trials in 13,680 people, adding live cultures went with eradication in 78.75% against 62.43% and about half the rate of diarrhoea (relative risk 0.49), alongside the course, never instead of it.⁶

Should you take live cultures before or after omeprazole?

No trial has compared taking the two together with taking them apart, so there is no gap to keep. The laboratory model is about meals, not medicines: a four-strain bacterial capsule survived best taken with a meal or 30 minutes before it, and poorly 30 minutes after one.⁷ Omeprazole's own timing is the NHS's line: "try to take it at the same time each morning" if you take it once a day, "with or without food".⁴ For the culture itself, see is it better to take a probiotic in the morning or at night.

What about SIBO, bloating and omeprazole?

Small intestinal bacterial overgrowth (SIBO) has a thinner record than the forums suggest. Neither cohort study measured overgrowth, and no abstract cited here says how often SIBO occurs on the medicine.^{1, 2} The one link between live cultures and overgrowth is a 2018 case series: 30 people with gas, bloating and "brain fogginess", all taking live cultures, compared with 8 with the same gut symptoms and no brain fog. Overgrowth was found in 68% against 28% (P = 0.05) and D-lactic acidosis in 77% against 25% (P = 0.006); after stopping the cultures and a course of antibiotics, symptoms improved in 23 of 30.⁸ It is a single-centre series, and a published reply argued that it does not show the cultures were the cause.⁹ Pooled across 18 studies in diagnosed overgrowth, the decontamination rate was higher with live cultures (relative risk 1.61) while new cases did not differ significantly.¹⁰ "If they make you worse, you have SIBO" is a forum claim no trial has tested. Persistent bloating is a GP matter; the NHS notes that omeprazole can "make it harder to notice symptoms of some serious conditions, such as stomach cancer".⁴

What supplements or medicines should not be taken with omeprazole?

The NHS list of what "may not mix well with omeprazole": other acid-reducing medicines such as lansoprazole and famotidine, the heart medicine digoxin, the anti-clotting medicines warfarin and clopidogrel, the sedative diazepam, the anti-seizure medicine phenytoin, the herbal remedy St John's Wort, and the HIV medicines nelfinavir and atazanavir.⁴ Live cultures are not on it. Their own interactions are with other medicines: many antibiotics kill bacterial cultures (timing on live cultures with antibiotics) and antifungal medicines inactivate yeast cultures.

How long can you take omeprazole for?

Some people take it for a few days and others "for several weeks, months or years", and it is not to be taken "for longer than 2 weeks if you bought it without a prescription"; see a GP if symptoms get worse or do not improve.⁴ The chance of serious side effects "can be higher if you take omeprazole for a long time", a year or more, so long-term use is something a GP reviews.⁴ Nothing on this page is a reason to stop, start or change a prescribed medicine.

Who should take care before taking live cultures?

Across 36 randomised trials in 9,312 adults taking antibiotics, side effects on a live culture were no more common than on placebo (relative risk 1.00).¹¹ The serious infections on record are rare: a review in people with cancer found five case reports of bloodstream infection, "a rare cause of sepsis".¹² Four groups ask their clinical team first: people with a weakened immune system, people who are seriously ill or in hospital with a central line, premature babies, and anyone whose doctor has said so. In a 2021 Cochrane review of trials that gave live cultures in pregnancy to lower the chance of gestational diabetes, pre-eclampsia was more common in the women who took them (relative risk 1.85, high-certainty evidence), so speak to a midwife or GP before any supplement in pregnancy.¹³ The full list is on when you should not take a probiotic.

What we don't know

• Outside prescribed H. pylori treatment, no randomised trial we found has measured a symptom, infection or overgrowth outcome for live cultures on omeprazole.
• Neither cohort abstract gives the dose or years of use, so nothing links length of use to the size of the shift.
• No trial has compared taking a live culture at the same time as omeprazole with taking it hours apart.
• The 2018 case series cannot say whether the live cultures or the overgrowth came first.

Frequently asked questions

Do probiotics stop omeprazole working, or omeprazole kill probiotics?

Neither, on the record. No trial reports live cultures changing how omeprazole works, and the NHS omeprazole page, reviewed 17 September 2025, does not list them among the things that may not mix well with it.⁴ The other way round, stomach acid is what a culture has to survive, and in the one randomised trial suppressing it meant more of the culture's species in the stool, not fewer.³

Can I take probiotics with lansoprazole or other PPIs?

The evidence is about the class: both 2016 cohorts grouped proton-pump inhibitors together, and one of the two randomised trials used pantoprazole.^{1, 2, 5} The NHS lansoprazole page, reviewed 3 December 2025, describes it as "a medicine that reduces the amount of acid your stomach makes", the same action as omeprazole.¹⁴

Is omeprazole a probiotic?

No. Omeprazole is a proton pump inhibitor, "a medicine that reduces the amount of acid in your stomach" in the NHS's words, used for stomach ulcers, heartburn, reflux disease and, with antibiotics, H. pylori.⁴ A probiotic, by the 2014 expert consensus definition, is "live microorganisms which when administered in adequate amounts confer a health benefit on the host".¹⁵ None of the trials on this page measured reflux symptoms; that record is on can probiotics cause acid reflux?

Can I drink kefir or live yoghurt with omeprazole?

Nothing in the record says not to. The NHS omeprazole page says "you can eat as normal while taking omeprazole", names no food among the things that may not mix well with it, and makes alcohol its one drink caution because it "can increase the amount of acid in your stomach".⁴ Kefir's own trial record is thin: a 2023 systematic review found 16 randomised trials, 12 at high risk of bias, with a possible role as an add-on to prescribed H. pylori eradication, a course that includes a proton pump inhibitor; none gave kefir or live yoghurt to people on omeprazole for anything else.¹⁶

Sources

1. Imhann F et al. Gut 2016. Observational, 1,815 people. PubMed 26657899
2. Jackson MA et al. Gut 2016. Observational, 1,827 twins. PubMed 26719299
3. Singh G et al. Clinical Nutrition ESPEN 2022. Randomised trial, 30 healthy adults, 6 weeks. PubMed 35063245
4. NHS. Omeprazole. Page last reviewed 17 September 2025. nhs.uk/medicines/omeprazole
5. Bibbò S et al. Helicobacter 2025. Randomised trial, 26 adults, 2 months. PubMed 40993967
6. Tanashat M et al. Clinical Nutrition ESPEN 2025. Pooled analysis of 91 randomised trials, 13,680 people. PubMed 39642994
7. Tompkins TA et al. Beneficial Microbes 2011. Laboratory model, one four-strain capsule. PubMed 22146689
8. Rao SSC et al. Clinical and Translational Gastroenterology 2018. Observational case series, 38 people. PubMed 29915215
9. Quigley EMM et al. Clinical and Translational Gastroenterology 2018. Letter. PubMed 30250026
10. Zhong C et al. Journal of Clinical Gastroenterology 2017. Pooled analysis of 18 studies. PubMed 28267052
11. Liao W et al. Journal of Clinical Gastroenterology 2021. Pooled analysis of 36 randomised trials, 9,312 people. PubMed 33234881
12. Redman MG et al. Annals of Oncology 2014. Systematic review, 17 studies, 1,530 people. PubMed 24618152
13. Davidson SJ et al. Cochrane Database of Systematic Reviews 2021. 7 randomised trials, 1,647 women. PubMed 33870484
14. NHS. Lansoprazole. Page last reviewed 3 December 2025. nhs.uk/medicines/lansoprazole
15. Hill C et al. Nature Reviews Gastroenterology and Hepatology 2014. Expert consensus statement on the term probiotic. PubMed 24912386
16. Kairey L et al. Nutrition Reviews 2023. Systematic review of 16 randomised trials of kefir. PubMed 35913411

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