Florastor is taken as one 250 mg capsule or packet twice daily, with or without food. Unlike bacterial probiotics, Florastor contains a yeast strain that is naturally resistant to antibiotics, which changes some of the usual rules about probiotic timing.
Standard Dosage for Adults and Children
Adults take one 250 mg capsule twice a day. The children’s version (Florastor Kids) follows the same twice-daily schedule but comes in powder packets instead of capsules. Most people take one dose in the morning and one in the evening, though the exact timing is flexible.
Capsules vs. Packets
If you’re taking capsules, you can swallow them whole with at least 4 ounces of water or juice. You can also open the capsule and mix the contents with soft food like applesauce or yogurt, or stir it into a cold, non-carbonated, non-alcoholic drink such as water or juice.
Powder packets work the same way: mix the contents into soft food or a cold beverage. One important detail is that once you mix the powder with food or liquid, you need to consume it within 30 minutes. The yeast is shelf-stable in dry form, but once it’s in a moist environment, its viability starts to change. Avoid mixing it into hot drinks, since heat can kill the live yeast before it reaches your gut.
Timing With Antibiotics
This is where Florastor differs from most probiotics. Bacterial probiotics are killed by antibiotics, so they typically need to be spaced a few hours apart from each dose. Florastor’s active ingredient is a yeast, not a bacterium, which makes it resistant to antibiotics. You can take it at the same time as your antibiotic without worrying about the antibiotic destroying it.
That said, starting Florastor early matters. In clinical trials studying antibiotic-associated diarrhea, participants began taking it within 24 hours of starting their antibiotic course. If you’re using Florastor specifically to prevent digestive side effects from antibiotics, begin as soon as possible after your first antibiotic dose.
How Long to Keep Taking It
If you’re taking Florastor alongside an antibiotic, don’t stop when the antibiotic course ends. In a randomized, placebo-controlled trial, participants continued taking Florastor for seven days after finishing their antibiotics. This makes sense because antibiotic-associated diarrhea can develop after the course is over, not just during it. Your gut flora needs time to recover, and the extra week of probiotic support bridges that gap.
For general digestive support unrelated to antibiotics, there’s no set stop date. Many people take it on an ongoing basis. If you’re using it for a specific episode of diarrhea, continuing for a few days after symptoms resolve is a reasonable approach.
Storage and Temperature
Florastor is stable at room temperature, which is unusual for a probiotic. Most bacterial probiotics need refrigeration to stay alive. You can keep Florastor in a medicine cabinet, travel bag, or desk drawer without worrying about potency loss. Just avoid storing it somewhere that gets very hot, like a car glove compartment in summer.
Side Effects
Most people tolerate Florastor well. Some experience mild gas or bloating when they first start taking it, which typically fades within a few days as the digestive system adjusts. These effects are more common in people who don’t regularly consume fermented foods or probiotics. If gas is bothersome, starting with one capsule per day for the first two or three days before moving to twice daily can ease the transition.
Who Should Avoid Florastor
Because Florastor contains a live yeast, it poses a real risk for two specific groups. People with central venous catheters (such as a PICC line or port) should not take it. The yeast can colonize the catheter and enter the bloodstream, causing a serious fungal blood infection called fungemia. Cases have been documented even when the probiotic was simply opened in the same room where the catheter was being handled, since airborne yeast particles can settle on the line.
People who are severely immunocompromised, whether from chemotherapy, organ transplant medications, or advanced HIV, should also avoid Florastor. A healthy immune system keeps the yeast confined to the gut, but a weakened one may not be able to prevent it from spreading. If either of these situations applies to you, a non-living postbiotic or a different approach to digestive support is a safer choice.