Can I Take Probiotics with Omeprazole?

Updated July 2026

Omeprazole is one of the most commonly used medicines in the UK for heartburn, indigestion and acid reflux, and it's a fair question whether adding a probiotic on top makes sense, or causes a problem. Here's what's actually established, and where the evidence is genuinely still developing.

So, can I take probiotics with omeprazole?

Yes. No confirmed interaction has been found between probiotics and omeprazole, and they're generally considered safe to take together. That said, "probiotic" covers a wide range of products, and omeprazole itself does have a number of confirmed interactions with other medicines, so it's still worth checking your full list of medications with a pharmacist rather than assuming everything is automatically fine together.

Does omeprazole affect your gut bacteria?

Yes, though not in the way "kills good bacteria" makes it sound. Omeprazole reduces stomach acid, and that acid normally acts as a barrier that stops less helpful bacteria from establishing themselves further down the digestive tract. With that barrier reduced, it becomes easier for other bacteria to colonise areas they otherwise wouldn't, which can shift the balance of your gut microbiome rather than wipe out the good bacteria directly. Long-term PPI use (a year or more) has also been linked to a higher risk of certain gut infections, including Clostridioides difficile, which is one of the reasons long-term use is only recommended under medical supervision.

Can probiotics help offset the effect omeprazole has on gut bacteria?

Possibly, and this is a genuinely active area of research rather than settled science. Some research has suggested that taking probiotics alongside a PPI may help support healthy bacterial colonisation and reduce some of the microbial disruption PPIs can cause. Other research looking specifically at whether probiotics prevent small intestinal bacterial overgrowth (SIBO) in children taking omeprazole has found more mixed results. As with all our probiotic content, "probiotic" doesn't carry an approved health claim in the UK or EU, so this is a description of where the research is heading rather than a promise of an outcome.

Should you take probiotics before or after omeprazole?

There's no strong evidence that timing them apart is necessary the way it is with antibiotics, since nothing in omeprazole is designed to kill bacteria the way an antibiotic is. Omeprazole is usually taken first thing in the morning before food, so many people find it simplest to take their probiotic with a later meal rather than at the exact same moment, mainly for convenience and routine rather than because taking them together causes a specific problem.

What supplements or medicines shouldn't be taken with omeprazole?

Omeprazole does have a number of genuine, well-documented interactions, and it's worth knowing the more significant ones. Clopidogrel (a blood-thinning medicine) is generally avoided alongside omeprazole, since omeprazole can reduce how well clopidogrel works. Omeprazole can also increase the blood-thinning effect of warfarin, meaning more frequent monitoring is often needed if you're on both. It can reduce how effectively the body clears methotrexate too, which raises the risk of methotrexate toxicity, particularly at higher doses.

Separately, long-term omeprazole use is associated with reduced absorption of certain nutrients, since stomach acid plays a role in how they're absorbed. Vitamin B12, magnesium, calcium and iron are the ones most consistently flagged in research, with studies showing meaningfully higher rates of deficiency in long-term PPI users compared with non-users. Vitamin D is a common exception worth knowing, it doesn't require an acidic environment to be absorbed, so it isn't affected in the same way.

This isn't an exhaustive list, omeprazole's full interaction profile is longer than we can responsibly cover here, so if you're taking regular medication, it's worth checking your specific combination with a pharmacist or your GP rather than relying on a general list online.

How long can you take omeprazole for?

Over-the-counter omeprazole shouldn't be taken for longer than 2 weeks without speaking to a doctor. If it isn't helping within that time, or you need it for longer, that's a sign to get it checked out rather than continuing to self-treat. The NHS notes that the chance of more serious side effects increases the longer omeprazole is taken, particularly with continuous use of a year or more.

Quick questions, quick answers

Does omeprazole kill probiotics?
No confirmed direct interaction has been found between the two. Omeprazole's effect on gut bacteria comes from reduced stomach acid changing the environment, not from directly killing probiotic bacteria you've taken.

How long does omeprazole take to work?
Many people notice some improvement within 2 to 3 days, though it can take up to about 4 weeks to have its full effect on symptoms.

Can long-term omeprazole use increase infection risk?
Yes, long-term use has been linked to a higher risk of certain gut infections, including Clostridioides difficile, which is one reason it's not recommended to stay on it long-term without medical supervision.

Should you tell your GP if omeprazole isn't working?
Yes. If over-the-counter omeprazole hasn't helped within 2 weeks, or you find you need it for longer than that, speak to your GP or pharmacist rather than continuing on your own.

None of this is medical advice. If you're taking omeprazole alongside other medications or supplements, a pharmacist can check your full list for interactions specific to you, which is a safer approach than relying on a general article.

Looking to support your gut day to day? Take a look at our gut health range.

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