What is Florastor?

Florastor is a probiotic supplement, which contains the probiotic yeast Saccharomyces boulardii (often abbreviated to S. boulardii). It is available in capsules for adults and flavored powder form for children. See our dedicated page on Florastor Kids for specific information regarding the children’s version of this supplement. Each adult capsule contains 5 billion colony forming units (CFUs)1 of probiotic yeast.


Florastor adult capsules contain the following ingredients:

  • Saccharomyces boulardii
  • Lactose
  • Magnesium stearate
  • Hydroxypropylmethylcellulose
  • Titanium dioxide

Florastor contains 33mg of lactose per serving (equivalent to one-third of the lactose found in a single slice of cheese). It is therefore not suitable for vegans.

As far as lactose intolerance is concerned, its manufacturers claim that the product is successfully taken by people who have difficulty tolerating lactose. Indeed some people who are lactose intolerant can manage very small amounts of lactose. It may therefore be that even if you are lactose intolerant, you will be able to digest the small quantity of lactose contained in this product.

We would however suggest that if you are lactose intolerant and wish to try this product that you begin with a very small amount of the product (perhaps a quarter of a capsule). If this proves to be OK, then ramp up your dosage slowly until you reach the full adult dosage of one whole capsule.

If on the other hand you experience symptoms on taking this product, which do not disappear with successive doses and therefore cannot be considered a die-off reaction, then this product is probably not for you.

The product may also contain traces of soy and so may not be suitable for those who are intolerant or allergic to soy.

However it is free from corn, gluten, egg and milk protein. It is therefore compatible with vegetarian and gluten-free diets.


Florastor has the advantage that it does not require refrigeration

Unlike many probiotic supplements, Florastor does not require refrigeration. It is thus ideal for taking on trips away where access to refrigeration may be limited. Provided the product is stored at room temperature (25°C or 77°F) and away from excessive moisture, it also has an impressive shelf-life of three years. Its shelf-life is much longer than many other probiotic supplements.

Another key advantage of using Florastor is that since the product contains probiotic yeast as opposed to probiotic bacteria, it is unaffected by antibiotic therapy. This means that you can take Florastor alongside your antibiotics.

Additionally the probiotic organism contained in this product, Sacchromyces boulardii, has been widely studied. In scientific trials it has been shown to be effective in reducing and preventing various diarrheas including travelers’ diarrhea2, antibiotic associated diarrhea3 and acute and chronic diarrhea4.

Furthermore when combined with antibiotic therapy Saccharomyces boulardii has been shown to be clinically effective in treating Clostridium difficile infection (also known as C. difficile or C. diff infection).

Treatment with Saccharomyces boulardii has been proven both to reduce C. difficile diarrhea5, and to lessen the recurrence of Clostridium difficile colitis (C. diff colitis), also known as C. difficile disease (CDD) and Pseudomembranous colitis (PMC)6,7.

There are also many positive user reviews for this product (See Amazon.com) with consumers reporting improvements in conditions including antibiotic associated diarrhea (ADD), Irritable Bowel Syndrome (IBS), Celiac Disease, intestinal yeast infection (Candida albicans), travelers’ diarrhea and Crohn’s Disease.


One disadvantage of Florastor is that is contains a number of additional ingredients

Florastor contains a good number of additional ingredients including lactose and so may be unsuitable for people experiencing food intolerance symptoms.

Compared to many other probiotic supplements, the product is also relatively expensive. See our cost comparison guide for more details on how to accurately compare the cost of different probiotic supplements. However, if you definitely want to try Saccharomyces boulardii but find the cost of Florastor just too prohibitive panic not! There are several alternative and cheaper products available on the market. These include supplements produced by Allergy Research Group (ARG), Nutricology and Jarrow respectively.

Our Evaluation

Florastor contains the probiotic yeast Saccharomyces boulardii

We’ve given Florastor a four star rating. It loses just one star for its low probiotic count and its additional ingredients. However, Florastor clearly is a helpful product and this is evidenced both by the clinical studies as well as by anecdotal reports from users. It’s also really handy – it does not require refrigeration and so is suitable for use "on the go".

Where Can I Buy Florastor?

Florastor is available from Amazon.com


You can also purchase it in many retail drugstores.


1.Colony forming units (CFUs) are a measurement of the number of viable bacteria contained in a product.

2.Kollaritsch H et al; Prevention of Traveler’s Diarrhoea. Comparison of Different Non-Antibiotic preparations; Travel Med In; 1989; 9–17

3.Surawicz CM et al; Prevention of Antibiotic-Associated Diarrhea by Saccharomyces Boulardii: a Prospective Study;Gastroenterology; 1989 Apr;96(4):981-8

4.Periti, P. et al; Preclinical and Clinical Pharmacology of Biotherapeutic Agents: Saccharomyces Boulardii; Journal of Chemotherapy; 2001; 13: 473:493

5.Castagliuolo I et al; Saccharomyces Boulardii Protease Inhibits Clostridium Difficile Toxin A Effects in the Rat Ileum; Infect Immun; 1996 December; 64(12): 5225–5232

6.Surawicz CM et al; Treatment of Recurrent C. Difficile Colitis with Vancomycin and Saccharomyces Boulardii; Am. J Gastroenterol; 1989; 84: 1284-1287

7.Surawicz CM et al, The Search for a Better Treatment for Recurrent Clostridium Difficile Disease: Use of High-Dose Vancomycin Combined with Saccharomyces Boulardii; Clin Infect Dis; 2000;31(4):1012

Return from Florastor to Probiotic Supplements

Share this page:
Enjoy this page? Please share it with others. Here's how..

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.

Most Popular Pages:

Best Retailer: Probiotics

Probiotic Supplements

Probiotics for Children

Baby Probiotics

Buy Florastor:

20 Capsules

50 Capsules

100 Capsules