Should you take probiotics with antibiotics?

What the evidence shows

• Antibiotic-associated diarrhea: in a 2017 review of 17 studies in people outside the hospital, probiotics roughly halved the chance. A review in children found moderate-quality evidence of a protective effect. Benefit hasn't been shown in older adults, though few were studied.
• C. difficile diarrhea: a 2017 analysis of 31 studies found moderate-certainty evidence that probiotics lower the risk in adults and children taking antibiotics. The best strains, doses and length of use are still uncertain, and guideline groups don't agree on routine use.
• Restoring gut bacteria: a 2023 expert panel from the International Scientific Association for Probiotics and Prebiotics (ISAPP) found no evidence that studied probiotics return the gut microbiome to its pre-antibiotic state.

Harvard Health notes there's no definitive evidence yet that everyone on antibiotics benefits, so it's a reasonable thing to discuss with your prescriber or pharmacist.

How to time probiotics and antibiotics

No studies have compared timing schedules, so there's no proven rule. An ISAPP resource for clinicians sums up what the trials did and what seems sensible:

1. Start early. Studies that showed a benefit usually began the probiotic before or within 1 to 2 days of the first antibiotic dose.
2. Space bacterial probiotics about 2 hours from the antibiotic. Antibiotics can kill most bacterial probiotics, so a 2-hour gap may be prudent, as long as it doesn't make you miss antibiotic doses.
3. Yeast probiotics don't need spacing. Saccharomyces boulardii isn't affected by antibiotics.
4. Keep going a little after. Continuing for 7 to 14 days after the antibiotic ends is a commonly tested approach.
5. Take the antibiotic exactly as prescribed. There's no evidence that probiotics make antibiotics less effective.

Which probiotics and foods

Cleveland Clinic says the most studied products for antibiotic-associated diarrhea are based on Lactobacillus rhamnosus or Saccharomyces boulardii. Results from one strain don't apply to others, so check the strain on the label, not just the brand.

Food is another option. Yogurt and kefir with "live and active cultures" add live microbes, though in smaller amounts than supplements. If diarrhea starts, a blander diet, plenty of fluids and easing off spicy food and alcohol can help. See probiotic foods.

When to call a clinician

C. diff is a bacterium that causes diarrhea and colon inflammation and can be life-threatening. CDC says the risk can be up to 10 times higher while you're on an antibiotic and in the month after.

Contact a clinician if you get diarrhea during or after antibiotics, especially with fever, belly pain or tenderness, nausea, loss of appetite, or blood in your stool. Don't stop an antibiotic early without talking to your prescriber.

People with weakened immune systems or serious illness should ask a clinician before taking any probiotic. A free Gabriel account pays cost-plus prices on supplements, and Gabriel Core and Plus member prices are lower still.