Probiotics and Antibiotics Together?

A probiotic is a preparation of live micro-organisms that, taken in adequate amounts, aims to support the community of bacteria already living in your gut. When a course of antibiotics is wiping out both the infection and a good share of your resident microbes, the obvious question is whether adding one helps or simply feeds the drug a target. The short answer is that you can take them together, and the trials that lowered antibiotic side effects did run both at once, but timing and strain choice decide how much good it does.

If you want the label-reading detail before the biology, our gut-brain probiotic guide covers strains and dosing, and the gut-brain hub sets out where a probiotic fits in a wider routine.

Why people pair the two in the first place

Antibiotics do not aim carefully. Alongside the bacteria causing an infection, they thin out the harmless and helpful species that keep the gut in balance, and one common result is loose stools. The point of taking a probiotic during treatment is to keep some beneficial organisms present while the drug does its work, so the gut has less room to be colonised by opportunists such as Clostridioides difficile.

The evidence for this is among the stronger areas of probiotic research. A Cochrane review by Goldenberg and colleagues (2017) found that probiotics given alongside antibiotics reduced the risk of C. difficile-associated diarrhoea in people who were not already at high risk, though the authors noted the quality of trials varied. An earlier meta-analysis in JAMA by Hempel and colleagues (2012) reached a similar conclusion for antibiotic-associated diarrhoea in general.

Does the antibiotic destroy the probiotic?

This is the practical worry, and the honest answer is: it depends on what you take. A bacterial strain such as Lactobacillus rhamnosus GG shares enough biology with the bugs the antibiotic is targeting that some of the dose can be knocked back. A yeast such as Saccharomyces boulardii is not a bacterium at all, so antibacterial drugs pass it by. That is one reason S. boulardii has featured heavily in the trials, including the meta-analysis by McFarland (2006), which found it lowered antibiotic-associated diarrhoea.

The usual compromise is to separate the two doses by about two hours. You are not trying to keep them apart forever, only to avoid delivering the live cultures at the moment the antibiotic concentration in the gut is highest.

Timing, in plain terms

Question	Practical answer
Same day?	Yes — trials dosed both on the same days
Same moment?	No — leave roughly two hours between them
How long to continue?	Through the course and one to two weeks after
Which strains studied most?	S. boulardii, L. rhamnosus GG

One caveat worth naming: recovery is not instant. Research by Suez and colleagues (2018) suggested that a generic probiotic can actually delay the return of a person’s own native microbiome after antibiotics, compared with letting it rebuild on its own. It is a single line of evidence and does not overturn the diarrhoea findings, but it is a fair reminder that “more bacteria” is not automatically “faster recovery.” The NIH Office of Dietary Supplements probiotics fact sheet is a level-headed overview if you want the wider picture.

What to look for in a probiotic to take alongside a course of antibiotics

The most useful thing on a label is a named strain, written out in full, such as Saccharomyces boulardii CNCM I-745 or Lactobacillus rhamnosus GG. A product that lists only a genus tells you little, because the evidence is strain-specific and a genus name covers hundreds of unstudied variants. Beyond that, check for a CFU count stated at the end of shelf life rather than at manufacture, a figure in the tens of billions for this use, and evidence of third-party testing for identity and purity. A yeast-based option removes the antibiotic-sensitivity worry entirely, which is why it is a common pick during a course. Our gut-brain probiotic guide walks through these criteria against a real label, and the gut-brain hub frames how a probiotic sits alongside diet. Match the choice to the reason your prescriber recommended it, not to whichever bottle claims the biggest number.

Cautions and interactions

For most healthy adults, taking a probiotic during antibiotics is low-risk, with mild bloating or gas being the usual complaints. The exception matters: people who are severely immunocompromised, critically ill, or have a central venous catheter have, rarely, developed bloodstream infections from probiotic organisms, so these groups should not start one without medical advice. A probiotic does not replace your antibiotic, shorten the course, or let you skip doses, and stopping the antibiotic early to “let the good bacteria win” is exactly how resistant infections take hold.

Because the right answer depends on the specific antibiotic, the reason it was prescribed, and your own health history, confirm the plan with the doctor or pharmacist who prescribed the antibiotic before you add anything.

This article is for general information and is not medical advice. Please see our disclaimer, and if you are struggling, our get help page lists support options.