Is florastor a probiotic?


Florastor is the brand name of saccharomyces boulardii, a probiotic available online and over-the-counter (OTC).

Probiotics contain different types of micro-organisms like yeast (saccharomyces boulardii) and bacteria. These micro-organisms (also known as flora) are naturally found in the stomach, intestines, and vagina.

Probiotics are marketed as a way to restore normal ratios of good yeast and bacteria in the system, helping maintain normal bowel movements, aiding digestion, and promoting intestinal health.

The theory is: “Good flora” or naturally occurring bacteria can get overwhelmed by “bad” bacteria (like viruses or parasites) that get into the digestive system causing diarrhea and other stomach issues, especially in travelers.

Probiotics naturally occur in some of the foods we eat like yogurt, milk, and soy beverages. They’re also available as a dietary supplement.

Florastor is one of many brands of probiotics on the market. Florastor was discovered in the 1920s by a French scientist, who found the tropical yeast Saccharomyces boulardii (S. boulardii) growing naturally on the skin of lychees and mangosteens in Indochina.

From that discovery a patent and company was born. The company, Biocodex, labeled its patented bacterial strain Saccharomyces boulardii lyo, now known commercially as Florastor.

It’s manufactured using a process called lyophilization (similar to freeze drying) that preserves billions of live S. boulardii cells in a powder. Biocodex is still an independent, family-owned French pharmaceutical company with subsidiaries in the United States.

Florastor has not been evaluated by the Food and Drug Administration (FDA) for safety or effectiveness. It’s been sold in Europe for more than 40 years but only became available in the United States in 2003.

Biocodex issued a warning that patients with a central line catheter to the blood stream should not come in contact with Florastor. The introduction of S. boulardii cells to a central line could cause fungemia (fungi or yeast in the blood). “Central lines” are defined as central venous catheters, peripherally inserted central catheters, and totally implantable devices or ports.

Florastor Warnings

Without FDA approval, all of the risks associated with Florastar may not be known.

Biocodex reports there have been no reliable tests on the effects of Florastor in pregnant women. They suggest consulting a doctor before use if you are pregnant or planning a pregnancy.

If you have persistent diarrhea (lasting more than two days), especially if it is accompanied by a high fever, contact a doctor or pharmacist before using Florastor.

Patients with a weakened immune system from chemotherapy or HIV infection should not take this product without talking to a physician first.

Also talk to your doctor if you have frequent vaginal infections or recurring urinary tract infections.

Tell your doctor and pharmacist about all medications you are taking including prescriptions, over-the-counter medications, vitamins and herbal remedies, and illegal or recreational drugs.

Why You Should Take Antibiotics With Probiotics

Antibiotics kill our probiotic bacteria. So knowing the benefits of probiotics, I avoid antibiotics whenever possible.

But, you should probably take antibiotics to avoid death or kill serious infections. And if you take probiotics together with antibiotics, you’ll reduce the damage that antibiotics do to our native probiotics.

Research Proves Probiotics Taken With Antibiotics Prevent Diarrhea

33% of people who take antibiotics alone suffer from post-antibiotic associated diarrhea.

But, for those who take probiotics with their antibiotics, the risk of diarrhea dropped by 42%.

Why Do Scientist Think Probiotics With Antibiotics Reduce Diarrhea Risk?

The primary cause of post-antibiotic diarrhea is infections by bacteria like C. difficile. I also think candida and parasite infections are a cause, but I haven’t seen research investigating those causes.

Scientists know that when you take antibiotics, you kill probiotic bacteria that form your intestinal protective barrier. With a compromised probiotic barrier, your intestines are more open to infection.

But, when you take probiotics with antibiotics, you help reinforce the probiotic barrier on your intestinal wall…making infection less likely…and decreasing the risk of post-antibiotic diarrhea by 48%.

What’s the Best Probiotic To Take With Antibiotics?

Based on my reasearch, the best probiotic strain to take with antibiotics is Saccharomyces boulardii (in the product Florastor).

I have 2 reasons why:

  1. You can take antibiotics and S. boulardii at the same time – other probiotics need to be taken 4 hours after taking antibiotics
  2. There’s strong research that the strain S. boulardii helps with post antibiotic diarrhea

Buy Florastor on Amazon: $33.00

How Soon After Antibiotics Can You Take Probiotics?

You can take S. boulardii at the same time as your antibiotics because S. Boulardii is a probiotic yeast…and probiotic yeast are unharmed by antibiotics (which target bacteria).

Last time I took antibiotics, I had 3 antibiotic doses a day – about every 6 waking hours. Each time I took an antibiotic, I took a 250mg Florastor pill at the same time…which was super convenient.

But, if I were to take a lactobacillus or bifidobacterium based probiotic, I would have to set a timer, and then wait 4 hours to take the probiotic. But, just 2 hours later I would have to take an antibiotic again – killing the probiotics I just took.

Now if I had only one dose of antibiotics every day, then it wouldn’t be as inconvenient to take a probiotic 4 hours later. I would still prefer to take Florastor in that case. But, in that case I could also take a broad spectrum probiotic like United Natural Synbiotic 365 or 1MD’s Complete Probiotic Patinum.

But again, because of the simplicity and convenience, I would still consider Florastor the best choice because a) it’s proven, and b) it’s easy to remember to take your antibiotics and your Florastor at the same time.

If you take S. boulardii, you can take antibiotics and probiotics at the same time.

If you take a lactobacillus or bifidobacterium based probiotic, then you should take the probiotic at least 4 hours after taking a dose of probiotics.

Florastor Probiotic Dietary Supplement, 250 mg, 20 Capsules

Item No. 0358174

Studied and trusted for over 50 years, Florastor Probiotic is pharmacist’s’ No. 1 choice for intestinal probiotics. The yeast-based probiotic naturally breaks down toxins and helps alleviate digestion issues. Promoting and supporting intestinal health, each capsule is specially-designed to maintain the balance of intestinal flora and keep intestines functioning harmoniously. Includes 20 capsule-shaped dietary supplements.

Features & Benefits:

  • Long term use of florastor is not associated with complications.
  • Florastor transits through the digestive tract attaining steady-state levels that are maintained throughout the administration period.
  • Do not mix florastor in any carbonated
  • Florastor can be taken with or without food
  • Restricted diets-florastor has 33 mg lactose it is proven to increase lactase production, which helps with the digestion of lactose It is a gluten free dietary supplement Note: florastor may contain traces of soy

“This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.”

Saccharomyces Boulardii

Adverse Effects: Gastrointestinal

The use of Saccharomyces boulardii probiotic (a subtype of Saccharomyces cerevisiae) leading to sepsis in an 8-year-old child was reported from Turkey. The child was in the surgical intensive care unit (ICU) and had a tracheostomy and central venous (CVC) line in place. He was given a probiotic containing multiple organisms including S. boulardii for reduction of diarrhea. The product was opened and diluted in water at the bedside for administration via gastrostomy. He had recurring fever on broad-spectrum antibiotics for an infected decubitus ulcer. Fungal infection was determined on CVC blood culture. A 14-day course of liposomal amphotericin B and removal of the CVC device successfully treated the infection. The authors did a literature review and found 15 additional pediatric cases of S. cerevisiae fungemia secondary to probiotic use in patients from newborn to 16 years of age. An IV catheter was present in 14 of 15 patients. One patient in this group succumbed to the fungemia. A caution is given by the authors for clinicians to weigh the risks of probiotic use for pediatric patients with immunocompromise, long-term hospital stay, especially in the ICU setting, CVC devices, and broad spectrum antibiotic use .

Seven cases of Saccharomyces fungemia in ICU patients, neonatal and adult, in India were associated with probiotic use. All but one of these confirmed cases had received probiotic products prior to diagnosis of fungemia, the one patient that had not received probiotics was in close proximity to patients who had. S. cerevisiae was present in blood isolates from the patients as well as in the probiotic products used by the patients. The S. cerevisiae were confirmed as the same organism using D1/D2 rDNA genotyping and antifungal susceptibility testing. The authors of this case series recommend avoiding use of probiotics for patients who are critically ill; especially those with CVC access .

A case of a middle-aged man receiving broad coverage antibiotics for recurrent UTI and community acquired pneumonia, who was intubated, had a CVC placed and admitted to an ICU, with subsequent S. boulardii fungemia was reported. He had received a probiotic containing S. boulardii from admission via nasogastric tube. The probiotic was opened and mixed in water at bedside. The organism causing the fungemia was typed as being the same as the organism from the probiotic product used by D1/D2 rDNA genotyping and proteomic analysis. The institution changed policy on patient selection and method of probiotic administration after investigating this event and based on the conclusions of a utilization review showing no benefit in patients from probiotic use in the ICU .

Appel da Silva and colleagues present a case report of S. cerevisiae var. boulardii in an oncology patient with a CVC in Brazil. The patient was prescribed several broad spectrum antibiotic courses for urinary tract infections which subsequently caused diarrhea. Due to this and a fever, the patient received a course of antiparasitic drug and a multiple organism based probiotic product at this point during therapy. Continued fever and a positive Clostridium difficile stool antigen screen prompted the discontinuation of the antiparasitic and the addition of metronidazole to the probiotic. Fever continued, so a central line culture was taken and revealed the growth of S. cerevisiae var. boulardii. Antibiotic therapy was altered, mycafungin therapy was started and probiotic treatment was discontinued. The central line was not removed. After this event, the authors revised their institution’s protocol to decrease utilization of probiotic products in critically ill patients with central lines to minimize the risk of fungemia .

Two adult patient cases from Turkey described S. boulardii systemic infections. The first was an 88-year-old man with urosepsis, subsequent septic shock and intubation. He received S. boulardii containing probiotic therapy to alleviate diarrhea caused by several days of carbapenem therapy. The patient developed a fever after probiotic institution and two subsequent blood cultures were S. boulardii positive. Probiotics were discontinued and fluconazole instituted with good results. The other case was a 38-year-old woman with pneumonia who was admitted to the ICU and intubated. She received probiotic therapy for diarrhea secondary to antibiotic therapy. Blood cultures revealed S. boulardii. This patient received fluconazole but later developed septic shock and died. Mycologic studies of the organisms from both cases were confirmed by genotyping to be the same as the organisms from the administered probiotic product. These authors also suggest caution against the use of probiotic products for patients in the ICU or who are immunocompromised .

The use of probiotics in the ICU should be limited to patients that may benefit. The preparation of probiotics for administration via enteral device should be in an area away from patients, especially those with central venous catheters or immunosuppression. Patients with conditions that warrant CVC devices, who have or are currently receiving broad spectrum antibiotics and who are immunocompromised should not receive probiotic products due to increased risk of developing fungemia or sepsis from species included in the products .

A case of pyogenic liver abscess and sepsis secondary to the use of a lactobacillus containing probiotic is described by Sherid and colleagues. The patient had a medical history of diabetes, hypertension and end stage renal disease. She had recently completed a course of antibiotics for Clostridium difficile colitis after complicated gall bladder surgery. She presented with non-specific symptoms—fever, malaise, nausea and vomiting. The liver abscess was found on CT scan of the abdomen after the discovery of hepatomegaly on physical examination. Cultures from the abscess included Lactobacilli species and gram-negative organisms which were not speciated, nor was the probiotic product. The abscess resolved on discontinuation of probiotic and the use of additional antibiotics .

Generic Name: saccharomyces boulardii lyo (SAK a roe MYE sees boo LAR dee eye LYE oh)
Brand Name: Florastor, Florastor Kids, Saccharomyces Boulardii+MOS

Medically reviewed by on Nov 26, 2019 – Written by Cerner Multum

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What is Florastor?

Florastor is a specific form of yeast also known as Brewer’s Yeast, Hansen CBS 5926, Levure de Boulangerie, and Probiotic.

Florastor has been used as a probiotic, or “friendly bacteria,” to prevent the growth of harmful bacteria in the stomach and intestines.

Florastor is likely effective in alternative medicine as an aid in preventing diarrhea caused by taking antibiotics, or by using a feeding tube. This medicine is also likely effective in treating diarrhea in babies and children.

Florastor has been used as a possibly effective aid in preventing the recurrence of diarrhea caused by Clostridium difficile (C. difficile). However, this product may not be effective in treating the first episodes of this type of diarrhea. This medicine is also possibly effective in treating “traveler’s diarrhea,” diarrhea in people with HIV, and stomach ulcers caused by Helicobacter pylori.

Other uses not proven with research have included irritable bowel disease, Crohn’s disease, ulcerative colitis, cystic fibrosis, urinary tract infections, yeast infections, lactose intolerance, and other conditions.

It is not certain whether Florastor is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. This medicine should not be used in place of medication prescribed for you by your doctor.

Florastor is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Florastor may also be used for purposes not listed in this product guide.

Important Information

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use Florastor if you are allergic to yeast, or if you are taking an antifungal medication such as:

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

  • weak immune system (caused by disease or by using certain medicine);

  • lactose intolerance;

  • if you are dehydrated; or

  • if you have a central IV line (venous catheter).

Ask a doctor before using Florastor if you are pregnant or breastfeeding.

Do not give any herbal/health supplement to a child without medical advice. A child with diarrhea should be checked by a doctor.

How should I take Florastor?

When considering the use of herbal supplements, seek the advice of your healthcare provider. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to take Florastor, use it as directed on the package or as directed by your healthcare provider, pharmacist, or other healthcare provider.

Do not use more of this product than is recommended on the label.

You may take Florastor with or without food.

Florastor is available in capsule and powder form.

Do not use different formulations (such as capsules together with powder) at the same time without medical advice. You may get too much of this product.

You may swallow the capsule whole, or open it and sprinkle the contents directly onto your tongue. Drink at least 4 ounces of water or juice when swallowing the medicine.

To use the oral powder, tear open the packet and empty the entire contents into at least 4 ounces of water, juice, or milk. Stir this mixture and drink all of it right away. To make sure you get the entire dose, add a little more water to the same glass, swirl gently and drink right away.

To make swallowing easier, you may also sprinkle the medicine from a capsule or from the powder packet into a spoonful of yogurt or applesauce. Swallow right away without chewing. Do not save the mixture for later use. Discard the empty capsule.

Call your doctor if the condition you are treating with Florastor does not improve, or if it gets worse while using this product.

Store this product at room temperature away from moisture and heat. Do not refrigerate.

What happens if I miss a dose?

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra Florastor to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking Florastor?

Follow your healthcare provider’s instructions about any restrictions on food, beverages, or activity.

Florastor side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Although not all side effects are known, Florastor is thought to be likely safe for most people when used as directed for up to 15 months.

Common side effects may include:

  • gas, bloating; or

  • constipation.

This is not a complete list of side effects and others may occur. Call your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Florastor?

Other drugs may affect Florastor, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

  • Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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Product Review

The use of probiotics for acute and chronic digestive diseases has been gaining popularity in the North American medical community for the past 5 years. From the Greek “for life”, “probiotics” are live bacteria or yeast cells that aid the damaged, dysfunctional, or inflamed bowel in digestion and absorption. Russian scientist Ilia Metchnikov, later awarded the Nobel Prize for his work, first discovered probiotics in the early part of the 20th century. In 1923, French scientist Henri Boulard was one of the first to discover a yeast-based probiotic while he was searching for yeast to make wine. During his travels to Indonesian countries, he met a local doctor who was using the peels of the litchi fruit as an anti-diarrhea agent. This yeast, now available in Canada as Florastor™ has sold 10 billion doses worldwide and is used to safely treat the broad spectrum of intestinal diseases found today.

How Does Florastor Work?

In a normal gut, there are billions of live bacteria and yeast organisms that line the bowel, aid in digestion, and maintain the body’s defense system. This ecosystem within the bowel is known as colonic flora. This flora is constantly combating pathogens (viruses, bad bacteria, and yeast) and it is only when there is an overgrowth of pathogens within the bowel that a problem occurs.

Probiotics such as Florastor – the most clinically researched probiotic worldwide – temporarily line the bowel with billions of live non-pathogenic (good) cells that aid in fighting the overgrowth of pathogens (bad cells) and return balance to the lining of the gut, thereby allowing the bowel to function normally.

Florastor enters the bowel and lines it with billions of harmless live yeast cells. These cells act as a temporary gut lining by naturally increasing the body’s immune system, which overpowers the toxins released by bad bacteria. Florastor also naturally increases the body’s production of digestive enzymes, which aid in digestion and nutrient absorption within the gut.

Florastor is helpful to:

  • Prevent or reduce duration of diarrhea
  • Induce remission in Inflammatory Bowel Disease
  • Decrease symptoms and flares in Irritable Bowel Syndrome
  • Decrease Clostridium Difficile
  • Decrease antibiotic induced diarrhea
  • Decrease Traveller’s Diarrhea
  • Decrease Pediatric Diarrhea
  • Improve lactose tolerance

Mechanism of Action

Bacteria exert their pathogenicity via toxins they introduce into the intestines. Important examples are cholera toxin, Escherichia coli (E. coli) enterotoxins, and Clostridium Difficile (C. Diff.) toxins. Florastor secretes a 54 KDa protein protease that neutralizes these toxins.

The toxin produced by vibrio cholera, cholera toxin, is known to increase the intercellular level of adenylate cyclase in intestinal epithelial cells. This triggers active secretion of chloride and bicarbonate resulting in diarrhea. Florastor was shown to inhibit approximately 50% of the water and sodium secretion. The bacterium C. Diff. produces two different toxins that have shown an up to 1,000-fold reduction in mice that are treated with Florastor.

Florastor has more than just an anti-toxic effect, however. It also increases the absorptive transport of chloride in intestinal electrolyte transport. As well, Florastor releases Polyamines (spermine, spermidine and putrescine), which help increase the activity of disaccharidases (enzymes such as lactase, maltase, and sucrase). This increase in the enzymatic activity could help with lactose intolerance. Finally, Florastor stimulates the production of Immunoglobulin A and Immunoglobulin G in the intestinal mucosa, which may help reduce the effects of the toxins.

Inflammatory Bowel Disease (Crohn’s disease, ulcerative colitis)

Inflammatory bowel disease (IBD) affects approximately 200,000 Canadians. This group of diseases includes Crohn’s disease and ulcerative colitis. Today we have many products that help improve symptoms in patients who are suffering from IBD. Unfortunately, most drugs used have a high number of side effects.

Florastor has been proven effective in treating symptoms of Crohn’s disease and ulcerative colitis when taken twice daily. Ask your doctor about adding Florastor to the products he or she has already recommended to help decrease the amount of gas, bloating, and diarrhea you may be experiencing. There are no known side effects or harmful drug interactions from using Florastor. Florastor is able to naturally restore the flora in the bowel, which helps reduce bowel inflammation.

Irritable Bowel Syndrome (IBS)

IBS affects approximately 20% of the North American population. The syndrome results in increased symptoms of abdominal pain, bloating and gas, constipation, and diarrhea. In clinical trials, taken twice daily, Florastor reduced the amount of diarrhea four fold in IBS patients. There was also an improvement in the feeling of overall ‘well being’ when Florastor was used.

Antibiotic Associated Diarrhea (AAD) and Clostridium Difficile

AAD occurs in approximately 30% of patients who are prescribed antibiotics. The purpose of taking antibiotics is to prevent or eliminate a bacterial infection in the body. Unfortunately, antibiotics not only kill the bacterial infection, but will also damage the naturally occurring good bacterial flora within your gut, causing an imbalance, which may lead to diarrhea. The use of Florastor once daily during your course of antibiotics will significantly reduce the incidence of diarrhea.

A further complication of taking antibiotics is the development of C. Diff, a particularly difficult bacterial strain that damages the colon and in some cases can result in hospitalization and death. Recent outbreaks of C. Diff in Calgary and Montreal have increased the need for proper prevention from AAD and proper treatment of C. Diff using probiotics.

Traveller’s Diarrhea

Approximately 50% of travellers visiting warm exotic climates suffer from diarrhea caused by the change in food and water in their new environment. You can prevent traveller’s diarrhea easily and safely by taking Florastor prior to going on – and throughout the duration of – a trip. The live cells line the bowel and protect the gut from an overgrowth of bacteria such as E. coli.

Pediatric Diarrhea

The World Health Organization – as part of a treatment program – has recommended probiotics like Florastor with standard oral re-hydration for children with acute diarrhea. Florastor, with a proven safety profile for children as young as 3 months, has been able to notably decrease the length of time a child suffers from diarrhea.
Not All Probiotics Are Created Equal

There are many probiotics available at your local pharmacy but, unfortunately, most are not manufactured under GMP (Good Manufacturing Practice) guidelines. This is a strict manufacturing process that all ethical pharmaceutical products must follow. It is a costly process for the manufacturer but results in the highest quality products. Florastor is produced under GMP guidelines and is certified as a pharmaceutical grade product in France. In addition, it is manufactured using a freeze-drying process, which ensures a three-year shelf life at the end of which the product is still effective. In addition, the company guarantees that the number of yeast cells in each capsule matches the claim on the label.

There have been many studies testing the ingredients in probiotics, and a recent study from the University of British Columbia found that most probiotics on the market do not contain the number of live cells their labels claim. In fact, most of them had no live cells at all, essentially making them as effective as a placebo.

Florastor, a pharmaceutical grade probiotic has a specialized formulation that protects the cells and allows for proper delivery of the live cells into your bowel.


Gastroenterologists, family doctors, pediatricians, and pharmacists across North America currently recommend probiotic therapies. Patients have successfully used these worldwide for the better part of this century. Florastor is a probiotic with proven efficacy and is produced in state-of-the-art manufacturing facilities that guarantee the final product. It is likely the use of probiotics will continue to grow in the future as more and more data are presented.

Par Nijhawan, MD, FRCPC, FACG
First published in the Inside Tract® newsletter issue 145 – September/October 2004
1. Brenda A. Huff, MD, CCFP “Probiotics” might not be what they seem. Can Fam Physician 2004; 50:583-587
2. R. Reimer. Pre and Probiotics: Significance and Clinical Impact in Clinical Practice. Clinical Nutrition Round March 2004

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