£6.79 £25.99
Includes 20% VAT
Product rated 4.7 in 69 reviews

Saccharomyces boulardii is a unique yeast and microorganism. This strain from OptiBac is scientifically proven to reach the gut alive.

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No Dairy No Dairy
No Gluten No Gluten
Vegan Vegan

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What's it for?

An extensively researched microorganism, proven to reach the gut alive.

Who's it for?

For anyone, 1 year and over, seeking a pure Saccharomyces boulardii supplement.

Each capsule:

Provides 5 billion live cultures of pure, shelf stable Saccharomyces boulardii.

OptiBac Saccharomyces boulardii

Saccharomyces boulardii is a natural and safe microorganism with vast scientific research and documentation.

This strain has been internationally acclaimed as a well-researched and unique microorganism, and has been safely used for the last 50 years. Saccharomyces boulardii is a natural food supplement, and not a medicine.

Saccharomyces boulardii is a unique microorganism which is sold widely in the US, Scandinavia, Germany & France. OptiBac Probiotics was the first UK company to make a pure Saccharomyces boulardii supplement. This friendly yeast is more robust to environmental stressors than more common bacterial live cultures, and shows strong resistance to heat, humidity and stomach acidity levels. These live cultures of S. boulardii have been tested and shown to be especially stable and resistant.

In terms of cost per billion microorganisms, our Saccharomyces boulardii supplement is the best value supplement containing S. boulardii currently available in the UK.

Saccharomyces boulardii can also be found in our supplement For travelling abroad (which contains 1 billion micro organisms per capsule, combined with other live cultures).

Saccharomyces boulardii under the microscope

More about OptiBac

All we do is live cultures; looking at different species and strains in detail. We are partnered with some of the world's leading institutes of microbiology; so when you're stressed with too much on your mind, you can rest easy - confident that you're choosing the experts.


Saccharomyces boulardii can be given to adults and children (from 1 year and over) with the following recommendations, or as professionally directed.

  • Take one to four capsules depending on severity of symptoms and up to six capsules daily, or as professionally directed
  • If taking anti-fungals, take separately (at least 2 hours apart).
  • For infants and children the dose should be lowered

  • Drink plenty of water with your course of live cultures.

  • For anyone unable to swallow capsules, capsule can be opened and contents mixed with a cold meal or beverage.

    See also Can I take 2 OptiBac supplements at the same time?


Like the rest of the OptiBac range, Saccharomyces boulardii does not require refrigeration.

Store out of direct sunlight.


Live cultures are not recommended for those with serious medical conditions eg. those who are severely immunosuppressed, have pancreatitis, are in the ICU, have melaena, have a central venous catheter, infants with short bowel syndrome, or to patients with open wounds following major surgery; unless under a doctor's care. Furthermore, pregnant or breastfeeding women should consult their doctor before taking Saccharomyces boulardii or 'For travelling abroad'.

Nutritional Information

Frequently Asked Questions

You can find more of our frequently asked questions on our FAQ page.


Delivery Options


As we are an UK-based company, the product prices on our website will always be shown in pounds sterling (GBP £). As currency exchange rates fluctuate on a daily basis, the conversion to local currency will be made by your bank on the day of purchase. Check out today's currency conversion rates using a search engine and an appropriate currency conversion tool, though do bear in mind that the rates displayed may be subject to change before your bank processes your transaction.

Next Day UK Delivery 

Order before 3pm from Monday – Friday and select option ‘next day delivery’ at the checkout for your order to arrive the next day.

Next Day: £6 - guaranteed next-working-day delivery to most of the UK* if you order by 3pm Monday to Friday (requires signature)

*excludes: Channel Islands, Herm Island, Isle of Man, Isle of Wight, Northern Irish postcodes BT18 & upwards, Sark, Scottish borders and offshore, and a small number of remote mainland destinations as determined by our delivery courier

UK Delivery 

UK delivery is free when you spend £100. The delivery discount is automatically applied at the checkout.

Once your parcel has been collected from our warehouse, we will send you a confirmation email to let you know that the parcel has been dispatched. For any further delivery queries, please call us on 01264 363 193 or email [email protected].

Orders placed before 3pm will be dispatched on the same working day.
Orders placed after this time will be dispatched the following working day.

Standard: £1.75 - please allow 4-7 days for delivery
First Class: £2.50 - please allow 1-3 days for delivery

Delivery within the United Kingdom and Northern Ireland has a fixed price, regardless of the size and weight of your order. Delivery times are estimates and not guaranteed unless otherwise stated.


We deliver to more than 50 countries and offer free delivery on orders over £100. The delivery discount is automatically applied at the checkout. Please see International Delivery Coverage below to find out if we deliver to your country.

Most international delivery prices are dependent on the size and weight of your order and where it is being sent. You'll be shown the final price of shipping in the checkout, before payment, once we have your address and order details. The main exception to this is delivery to EU countries using our International Express Courier service. This has a fixed delivery cost for each country, regardless of the size of your order.

  • I started taking this for long term morning diarrhoea (no other symptoms) just after my GP had requested an urgent referral for an endoscopy. I saw the consultant today, 9 days after taking it and he was amazed when I told him that literally overnight my symptoms had virtually disappeared and they had improved my quality of life and confidence. He didn't seem to know about the benefits of this particular probiotic even though there are so many good reviews and reports online. More research persuaded me to take zinc picolinate too which apparently has been given to children in Africa for years for similar symptoms. I think we have a lot to learn about digestive problems. My consultant still wants me to have a colonoscopy but that's mainly because I'm in my sixties which increases my risk of bowel cancer and being realistic, neither of us can be sure about the source of the problem and whether the initial improvement will continue. I would recommend anyone suffering from IBS-D to try this product - I've not had to take a single dose of loperamide since using it.

  • I was recommended S. Boulardii to take to help eradicate my systemic candida problem. I had previously taken Optibac's 'For Women' for candida/thrush, which really helped clear it up in the short term, but as my symptoms still flared up over time I was told that I probably needed to clear it from the gut to stop it recurring - S.Boulardii sticks to and removes the candida yeast from the gut.

    I was also recommended 'For every day EXTRA strength' at the same time, to repopulate and re-balance the gut with friendly bacteria. Although this initially seemed to me a lot to take on, I was really pleased to find my symptoms FINALLY stop! I had been suffering on and off from candida for a year and a half, until this treatment recommended by Optibac - it has been a real breakthrough. Thank you so much Optibac!

    S. Glos
  • I wanted to thank you for your help. My grandmothers upset stomach issues have resolved immediately after taking your probiotics. I can't stress how much this helps her quality of life at 92.
    She ... Read more

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