Saccharomyces Boulardii

16 capsules



(ex. tax) was: $11.99
4.6/5 (76 reviews) Read verified product reviews

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Suitable for



Gluten free

Gluten free



Dairy free

Dairy free

GMO free

GMO free

See full ingredients list


This highly researched supplement from Optibac Probiotics provides 5 billion CFU of pure Saccharomyces boulardii, clinically trialled and shown to support gut health especially in those with occasional diarrhea*. 

saccharomyces boulardii press

Probiotic Strains

  • Saccharomyces boulardii
  • Product Description

  • How To Use

  • Ingredients

  • Help & Advice

  • Reviews

  • Delivery & Returns

  • Product Description

    Who is Optibac Probiotics Saccharomyces Boulardii for​?

    For those with occasional diarrhea*.

    Key benefits

    • Saccharomyces boulardii is an extensively researched, internationally acclaimed probiotic which has been used safely around the world for over 50 years
    • Scientifically researched and shown to support digestive health, most notably for occasional diarrhea*
    • Also shown to reduce inflammation in the gut and address the overgrowth of bad bacteria or yeasts e.g. Candida*
    • Scientifically proven to survive stomach acidity and reach the gut alive
    • Each capsule provides 5 billion CFU of pure Saccharomyces boulardii guaranteed until end of expiry
    • Complements your natural gut bacteria
    • Easy to take on the go – no refrigeration required
    • Suitable from 1 year onwards
    • Can be used intensively or on an ongoing basis
    • As featured in Women's Health, and highly praised in TripAdvisor forums
    • From the UK’s most trusted & recommended brand of friendly bacteria supplements. As determined in an independent survey of 1000 British women+.

    Available to purchase in three pack sizes of 16, 40 or 80 capsules.

    Now dispatching in our new look!

    We are introducing new, eco-conscious packaging this year, and the new designs will update gradually from product to product to minimize any waste. Please bear with us as you may receive orders with both current and new packaging over the coming months. We hope you like the new look!

    We’ve reduced the plastic in this packaging by 96%. We no longer use plastic containers.

    Update July 2021: The full name for this supplement is Optibac Saccharomyces boulardii though this is shortened to S. Boulardii on the front of the packaging. It was formerly called ‘For bowel calm’ outside of the EU.

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    Customer feedback collected via independent review platform Trustpilot. See 'Reviews' tab for more customer opinions collected via our own website.

  • How To Use

    Recommended use

    Natural dietary supplement suitable for adults and children (from 1 year onwards) with the following recommendations:

    • Take 1 capsule daily. May be increased up to 6 capsules daily as desired (depending on severity of symptoms), or as professionally directed.
    • For young children the use should be lowered. 1 capsule daily, may be increased up to 3 capsules daily.
    • If taking anti-fungals, take separately (at least 2 hours apart).
    • For those unable to swallow capsules, open and mix contents with a cool drink/food.

    Storage instructions

    • For best results, do not remove desiccant sachet from the glass jar and close lid firmly after each use.
    • Store in a cool, dry place below 25°C (77 °F) and out of direct sunlight.

    Customer Questions

    All questions answered by probiotic experts Dr Kate Stephens PhD (Food and Microbial Sciences) BSc(Hons) Medical Microbiology and Kerry Beeson BSc (Nut. Med.) Nutritional Therapist.

    Is Saccharomyces boulardii a well-known probiotic strain?

    Saccharomyces boulardii is an internationally acclaimed strain; in fact, it is one of the most highly researched probiotics in the world! The unusual thing about it, however, is that it is actually a yeast, rather than a type of bacteria, and is the only known yeast to be classed as a probiotic1. It has been used safely2,3 for over 50 years worldwide to support occasional diarrhoea4 and overall gut health*3,5.

    How many Saccharomyces boulardii capsules should I take a day?

    As we all have a unique gut microbiome and varying health priorities, the response to Saccharomyces boulardii is different for each individual. You can take up to a maximum of 6 capsules per day, but it is recommended to start with 1-2 capsules per day and build up from there as required. When taking a higher number of capsules (3-6 capsules) it is advised to spread these across the course of the day, though if you have a particularly upset stomach, you can take 3-4 capsules together initially.

    What time should I take Saccharomyces boulardii?

    There is no right or wrong time of the day to take Saccharomyces boulardii, so whenever fits in with your schedule is fine. This probiotic yeast is more robust to environmental stressors than more common bacterial probiotics, and shows strong resistance to heat, humidity, and stomach acidity levels. It doesn’t need to be refrigerated and can be taken with or without food.

    Can I take Saccharomyces boulardii alongside other probiotic supplements?

    Yes, and it is recommended to do so. Saccharomyces boulardii works differently to other probiotic supplements because this ‘friendly yeast’ does not colonize for long in the gut. On its way through the digestive tract, however, it has many positive effects*, helping to heal the delicate gut lining5 and displacing certain bad bacteria or unfriendly yeasts6.


    Probiotics are not recommended for those with serious medical conditions e.g. those who are severely immunosuppressed, have pancreatitis, are in the ICU, have melaena, have a central venous catheter, short bowel syndrome, or patients with open wounds following major surgery; unless under a doctor's care. Keep out of reach of children.

    This is a dietary supplement and is not intended to prevent, treat or diagnose any medical conditions. Probiotic supplements should not be used as a substitute for a healthy diet and lifestyle. If you are taking any medications or have a serious medical condition, consult a doctor before use. Optibac supplements will not cause dependency and may be used on an ongoing basis.

    Pregnant or breastfeeding women should consult their doctor before taking Saccharomyces boulardii.


    1. Czerucka D, Piche T, Rampal P. Review article: yeast as probiotics -- Saccharomyces boulardii. Alimentary Pharmacology & Therapeutics. 2007 Sep;26(6):767-778. DOI: 10.1111/j.1365-2036.2007.03442.x.
    2. McFarland L.V., (2010), ‘Systematic review and meta-analysis of Saccharomyces boulardii in adult patients’. World Journal of Gastroenterology, 16(18):2202–2222.
    3. Kelesidis T, Pothoulakis C.(2012) ‘Efficacy and safety of the probiotic Saccharomyces boulardii for the prevention and therapy of gastrointestinal disorders’ Therapeutic Advances in Gastroenterology. 2012;5(2):111-125.
    4. Das S, et al. (2016) Efficacy and Safety of Saccharomyces boulardii in Acute Rotavirus Diarrhea: Double Blind Randomized Controlled Trial from a Developing Country. J Trop Pediatr. Dec;62(6):464-470
    5. Qamar et al., (2001), ‘Saccharomyces boulardii Stimulates Intestinal Immunoglobulin A Immune Response to Clostridium difficile Toxin A in Mice’. Infect. Immun., 69(4):2762–2765.
    6. Murzyn et al., (2010), ‘Capric Acid Secreted by S. boulardii Inhibits C. Albicans’. Plos One, 5(8):

  • Ingredients

    Ingredients saccharomyces boulardii supplement fact panel

    • Probiotic cultures: Saccharomyces boulardii (275mg)
    • Hydroxypropyl methylcellulose

    Each capsule guarantees 5 billion CFU.


    • Vegan
    • Vegetarian
    • Dairy free
    • Gluten free
    • Soy free
    • GMO free
    • No added sugars
    • Free from artificial flavorings, colorings and preservatives
    • No chemicals or parabens
  • Help & Advice

    Talk to our experts

    If you have a specific question or need some advice on which product to choose please email or click on the link below for our contact form

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  • Reviews

    Customer reviews

    • I have tried other probiotics but I have found Optibac S. Boulardii suits me very well and I can tell the effect even on the improvement in my skin. Customer service couldn’t have been more courteous and helpful when I emailed about a question I had.

      Mrs Judy Morris - 9th November 2021

    • I am a big fan of Optibac probiotics I am a big fan of Optibac probiotics. They are consistently great quality & are always delivered well packaged & quickly. Highly recommended

      Nina - 2nd September 2021

    • I had left a review earlier stating that this S. Boulardii product caused some uncomfortable side effects, and customer service responded very quickly. They have been very friendly and attentive to me, and I really appreciate it.

      Courtney - 28th July 2021

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  • Delivery & Returns

    USA Shipping

    Coronavirus Update

    We ship all USA orders from our warehouse in Hampshire in the UK. Due to the ongoing global pandemic many US, European and Worldwide postal routes are seeing increased transit times. Delivery times provided on this site are therefore a guide and not a guarantee. Express Services largely remain unaffected however these routes are typically subject to local tax and duties at customs.

    USA standard shipping: $4.99

    International postal order - typically deatched and delivered within 5-10 working days.
    Free standard shipping on orders over $100.

    USA express shipping: $6.99

    We use DHL and orders are typically dispatched and delivered within 2-5 working days.



    Good to know

    • We'll send you an email to confirm once your parcel has been dispatched.
    • For delivery queries, please email
    • We are unable to ship orders to PO boxes.
    • Product prices on this website are always shown in US dollars (USD $) and exclude tax - tax is not applicable as orders are fulfilled from the UK.

    Worldwide Delivery

    • We deliver to more than 50 countries.
    • Shipping is charged at cost - please note that duties may apply.
    • Please allow 3-7 working days for delivery within Europe and 5-12 days to all other destinations. Includes order tracking.  
    • If you are located within the United Kingdom or Europe, we recommended switching to our UK website.
    • International deliveries might currently take a little longer due to the global coronavirus situation. Please refer to the webpage of our international delivery provider DHL to confirm the number of days it takes to receive your order and whether they currently ship 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.
    • Long distance shipping and short-term exposure to high temperatures will not compromise the viability of our products. Customers living in very hot countries should store the products out of direct sunlight and refrigerate if the option is available.

    For more details regarding international orders, currency conversion and applicable tax for orders outside the USA, please take a look at our delivery FAQ.

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