Should You Take Probiotics With Antibiotics? Where It Fits

If you want to try probiotics with antibiotics, take them during the course, not only after. Start within the first two days of the course. Keep a bacterial probiotic about 2 hours away from each antibiotic dose, as long as that never makes you late on the antibiotic. Many studies then kept it going for 7 to 14 days after the last pill. A yeast probiotic (Saccharomyces boulardii) needs no gap from the antibiotic.

That plan comes from a clinician guide by the International Scientific Association for Probiotics and Prebiotics (ISAPP) and from the NIH Office of Dietary Supplements. ISAPP is a nonprofit science group led by academics, with member companies that pay dues. It is clear about the limits: "There are no studies that compare different dosing regimens, so optimal approaches are unknown." So the 2-hour gap is a careful guess, not a tested rule. If you have a weakened immune system or a central line, talk to your doctor before you start any probiotic (more on that below).

This article provides general information about medication management and is not a substitute for professional medical advice. Consult your doctor or pharmacist for advice specific to your medications.

Should I Take Probiotics With Antibiotics or After?

During, then after. The studies that found a benefit started early. ISAPP says they "typically commenced dosing as soon as is practical, either before or within 1-2 days after antibiotic initiation." The NIH fact sheet says reviews found that starting certain probiotics "within 2 days of the first antibiotic dose" helped lower the risk of antibiotic diarrhea in some groups.

How Long After Antibiotics Should I Take Probiotics?

For the "after" part, ISAPP says "continuing probiotics for 7–14 days post-antibiotics is a commonly tested dosing strategy." Study plans vary, so there is no single right number of days.

One well-known study points the other way. A 2018 study in Cell found that in mice and people, a mix of probiotic strains taken after antibiotics slowed the return of the usual gut bacteria, and the return stayed incomplete. That finding is about gut bacteria, not diarrhea.

How Many Hours Apart Should Antibiotics and Probiotics Be?

About 2 hours for most bacterial probiotics. ISAPP explains that most bacterial probiotics "are sensitive to a range of antibiotics," so a gap lowers the chance that the antibiotic inactivates the probiotic first. Its exact words: a 2-hour gap "may be prudent, provided this does not reduce compliance."

Canada asks for a bit more on paper. Health Canada's probiotics monograph is a guide for what probiotic labels in Canada say. For bacterial products the direction is: "Take at least 2-3 hours before or after antibiotics." Its listed sources are a 2011 MedlinePlus page, a 2006 pharmacists' handbook and a 2005 overview, not a trial that compared gaps.

Two rules sit above any number:

1. The antibiotic does not move. Keep it on the schedule your prescriber gave you. ISAPP's own condition is that the gap must not cost you antibiotic doses. If it does, drop the gap and talk to your pharmacist. Here is what to do if you miss an antibiotic dose.
2. The probiotic moves around the antibiotic, because antibiotic doses need steady spacing.

Probiotics With Antibiotics Timing: A Schedule for 1 to 4 Doses a Day

Here is one way to fit a bacterial probiotic around common antibiotic schedules, with at least 2 hours on each side. The antibiotic times are only examples. Use your own antibiotic schedule.

Four doses a day leave the shortest gaps, so aim for the middle of the longest daytime gap. If your probiotic label says to take it more than once a day, use more than one open spot. Our guides to three times a day and four times a day cover the antibiotic side of these schedules. For the food side of the probiotic itself, see the best time to take probiotics.

A yeast probiotic can skip this table and go with any antibiotic dose.

Do Antibiotics Kill Probiotics? Bacteria vs. Yeast

It depends on what is in the bottle. Check the ingredient list for the names below. The quotes in this table are from ISAPP's clinician guide, and the Canadian gaps are from Health Canada's monograph.

If a product has both bacteria and yeast in it, both gaps apply.

Yogurt and kefir come with two catches. First, ISAPP notes that "not all products with live microbes contain validated probiotics." Second, they are dairy, and some antibiotics have their own rule about dairy. Our antibiotics and dairy guide lists which ones and how long to wait.

Can You Take Probiotics With Fluconazole?

This is where the answer flips. Antibiotics can raise the odds of a vaginal yeast infection. The CDC lists "current or recent antibiotic use" as a risk factor. So an antifungal pill or cream may be your next prescription.

Antifungals are made to stop yeast, and Saccharomyces boulardii is a yeast.

• Cleveland Clinic's S. boulardii page lists "Medications for fungal infections, such as fluconazole or ketoconazole" under possible interactions.
• Florastor's Canadian label says taking it with antifungals that act in the gut "may decrease the efficacy" of the probiotic.
• Health Canada tells yeast probiotic labels: "Take at least 2-3 hours before or after taking antifungal medications."

Florastor's label describes this as the probiotic working less well. So the probiotic that needs no gap from your antibiotic is the one that needs a gap from your antifungal. If you take a yeast probiotic and get an antifungal, ask your pharmacist whether to space them, pause the probiotic, or switch types.

Do Probiotics Actually Help While on Antibiotics?

For diarrhea, they help some people. For "restoring" your gut bacteria, that has not been shown.

For ordinary antibiotic diarrhea, a 2021 review of 42 trials with 11,305 adults found a 37% lower risk when probiotics were taken with antibiotics. But in studies where the risk of diarrhea was low to begin with, there was no difference.

C. diff is a germ that can cause severe diarrhea after antibiotics. For this outcome, a 2025 Cochrane review pooled 38 trials with 13,179 people. C. diff diarrhea happened in 1.6% of people taking probiotics and 3.2% of people not taking them. That is about 1 case prevented for every 65 people, and the authors rated the evidence low certainty. They also noted that 28 of the 47 studies in the review had ties to probiotic companies.

Gut recovery is a different story. A 2023 review found no difference in gut bacteria diversity with probiotics during antibiotics. ISAPP's summary: "it is not possible to conclude that probiotics are able to restore an antibiotic-disrupted microbiome to a pre-antibiotic exposure state."

Who Should Not Take Probiotics With Antibiotics?

Ask your doctor before you start if any of these apply to you. ISAPP's clinician guide says "caution is still warranted in the immunocompromised, severely ill, premature infants and those with indwelling intravenous catheters." Florastor's Canadian label also says not to use it if you are allergic to any of its ingredients, especially yeast.

If you have a weakened immune system

Health Canada's label guide says: "Do not use if you have an immune-compromised condition (e.g. AIDS, lymphoma, patients undergoing long-term corticosteroid treatment)." If you take a steroid such as prednisone long term, that last example may be you. The NIH says probiotics have been linked to a few serious blood infections, mostly in people who were "severely ill or immunocompromised."

If you have a central line, PICC line or port

Florastor's Canadian label says not to use it "if you have a central venous catheter." It also says: "Very rare cases of fungemia have been observed in patients with central venous catheters." Fungemia means yeast or other fungi in the bloodstream. The label also says not to open the capsules near someone who has one. That label is for a yeast probiotic.

If you are in the hospital or ICU

In one ICU outbreak, yeast blood infections were traced to an S. boulardii probiotic. The outbreak stopped when the unit stopped using it.

If the probiotic is for a premature baby

In October 2023 the FDA warned that preterm infants given probiotics "are at risk of invasive, potentially fatal disease, or infection." The FDA has not approved any probiotic as a drug for infants of any age.

Watery Diarrhea While on Antibiotics: When It's Not a Probiotic Problem

The CDC says C. diff infection "can be life-threatening." Most cases start while or soon after taking antibiotics. People are up to 10 times more likely to get it during an antibiotic and in the month after. Its symptoms include diarrhea, fever, stomach tenderness or pain, loss of appetite and nausea. Not all diarrhea on antibiotics is C. diff, but the CDC says to contact a health care professional if you get diarrhea while on or after an antibiotic.

Health Canada's probiotic label guide points the same way. It says to ask a health care practitioner before use if you have "fever, vomiting, bloody diarrhea or severe abdominal pain." Florastor's Canadian label is stricter and says not to use it with any of those, or with nausea. Health Canada also says to stop the probiotic and ask if stomach upset, such as diarrhea, starts, gets worse or lasts past 3 days.

So if you get diarrhea on an antibiotic, call your prescriber, and call right away if it comes with fever, belly pain or blood. Do not stop the antibiotic on your own.

How Pillo Helps

An antibiotic plus a probiotic is two schedules with two different end dates. The antibiotic stops when the course does. The probiotic may keep going for another week or two.

Pillo lets you set each one at its own times, so the probiotic reminder lands in the gap you picked. Its persistent alarm keeps ringing until you act, which helps with an antibiotic you take three or four times a day. If the antibiotic is for your child or a parent, Pillo's Dependents feature is free for up to 2 dependents, and their alarms ring on your phone. Pillo is free for unlimited medications, with ads.

Download Pillo on Google Play

FAQ

Can I take a probiotic at the same time as my antibiotic?

A yeast probiotic, yes. ISAPP says Saccharomyces is "unaffected by antibiotics." For a bacterial probiotic, ISAPP suggests about 2 hours apart, but only if the gap does not cost you antibiotic doses. Taking the antibiotic on time comes first.

Do probiotics make antibiotics less effective?

On that worry, ISAPP says: "There is no evidence for this concern." Its reasoning is that antibiotics already meet a huge number of microbes in your gut "and still remain effective."

Should I take probiotics with antibiotics for a UTI?

If you try one, the same timing rules apply, because what matters is the antibiotic, not the infection. The CDC lists recent antibiotic use as a risk factor for vaginal yeast infections. If you get one and need an antifungal, tell your pharmacist which probiotic you take.

Can I give my child probiotics with antibiotics?

Ask your child's doctor first, since the product and amount are their call. Never give a probiotic to a premature or hospitalized baby unless the care team says to. The FDA warned in 2023 that it can cause serious infection in preterm infants.

Is taking probiotics while on antibiotics pointless?

Not for diarrhea. A 2021 review of adult trials found 37% less antibiotic diarrhea with probiotics, though studies with a low starting risk showed no difference. Probiotics have not been shown to restore your gut bacteria, though.

This article is for informational purposes only and does not constitute medical advice.