Probiotics and Travel: Preventing Traveler's Diarrhea and What Travel Health Bodies Say
What the travel-medicine guideline and meta-analyses say about taking probiotics to prevent traveler's diarrhea, why results differ by strain, and when to see a clinician before or after a trip.
Content last updated . This page has not been medically reviewed.
Start here: when travel diarrhea needs medical help
Most diarrhea after a stomach bug settles by itself, and the NHS (UK) says the most important step is plenty of fluids to avoid dehydration. [1] Get urgent medical advice for bloody diarrhea or bleeding from the bottom, for diarrhea lasting more than 7 days or vomiting for more than 2 days, or if a baby under 12 months is involved. [1] The NHS also says older people, people with a weakened immune system and people with other health conditions are at greater risk of dehydration and should speak to a pharmacist. [1] The NHS says not to give children under 12 medicine to stop diarrhea. [1] Abroad, local emergency services and a travel insurer's helpline apply; this page is general information only. A pre-travel visit with a clinician or travel clinic is the place to discuss your own risk and any prescription options.The short answer
Travelers' diarrhea (TD) is diarrhea that starts during or soon after a trip. The question here is narrow: does taking a probiotic before and during a trip lower the chance of getting it? The evidence is mixed and strain-dependent. A 2017 clinical practice guideline from the International Society of Travel Medicine (ISTM), as described by NCCIH, stated that there is insufficient evidence to recommend probiotics or prebiotics to prevent or treat traveler's diarrhea. [2] NCCIH added that the guideline acknowledged evidence suggesting a small benefit, but that studies vary greatly in strains used, causes of diarrhea and geographic locations. [2] Proper evidence not found in the sources we read for a current statement by a national travel-health service: the US CDC Yellow Book page returned an access error (HTTP 403) and the NHS travel-health pages we tried were not available, so we do not cite them.What reviews found
Evidence labels used: mixed, promising but limited, insufficient evidence.| Review | What it found | Label |
|---|---|---|
| 2007 meta-analysis, 12 randomized trials | Pooled risk ratio 0.85 (95% CI 0.79 to 0.91): probiotics significantly prevented TD overall; Saccharomyces boulardii and a mixture of Lactobacillus acidophilus and Bifidobacterium bifidum each had significant efficacy; no serious adverse reactions were reported in the 12 trials [3] | Promising but limited (older, pooled across products) |
| 2018 review of 11 studies (5,143 participants), via NCCIH | Evidence that probiotics or prebiotics may help, but the review did not assess study quality or include data on side effects [2] | Insufficient |
| 2019 meta-analysis, strain-level (12 trials systematic review, 6 in the meta-analysis) | Saccharomyces boulardii CNCM I-745 significantly reduced TD incidence (risk ratio 0.79, 95% CI 0.72 to 0.87); Lactobacillus rhamnosus GG showed a trend; L. acidophilus showed no significant reduction; only one of three probiotics showed significant efficacy [4] | Mixed; one strain only |
| 2024 network meta-analysis, 31 studies (10,879 participants) of bismuth subsalicylate, probiotics, rifaximin and vaccines | Bismuth subsalicylate and rifaximin were more effective than placebo and the other options; rifaximin had lower TD incidence and lower adverse event rate (moderate confidence) [5] | Insufficient for probiotics specifically |
Notes on reading this table. The 2019 result belongs to one product containing a specific yeast strain, not to probiotics in general, and not to yogurt or other foods. [4] Pooling many different products, as the 2007 analysis did, may hide that only some work. [3][4] The numbers are results from trials, not recommended amounts; this page does not give a dose, a start date or a schedule. NCCIH gives the strains used, the causes of the diarrhea and the destinations as reasons results vary. [2]
How this fits with other options
The ISTM guideline abstract says strong evidence supports antimicrobial therapy in most moderate to severe TD, and that fluids alone, loperamide or bismuth subsalicylate may suffice for most mild cases. [6] Those are medicines or treatments to discuss with a clinician or pharmacist; the guideline does not make probiotics part of that list in its abstract. [6] Prescription prevention and self-treatment plans are decided by a travel clinic, not by this page. For general advice see Diarrhea: Causes, Dehydration and When to Get Help, and for condition-level evidence see Probiotics for Infectious Diarrhea and Traveler's Diarrhea.Frequently asked questions
Should I take a probiotic before a trip to prevent diarrhea?
The ISTM guideline, as described by NCCIH, found insufficient evidence to recommend it, though some trials suggest a small benefit. [2] Discuss with a clinician or travel clinic.
Which probiotic works best for travelers' diarrhea?
A 2019 meta-analysis found a significant reduction only for Saccharomyces boulardii CNCM I-745 among three tested. [4] That does not make it right for every traveler, and no ranking is implied.
Are probiotics safer than antibiotics for travel?
Proper evidence not found in the sources we read for a direct head-to-head safety comparison. A 2024 network meta-analysis found rifaximin had lower TD incidence and lower adverse event rate than the other options studied. [5] Medicine choices belong to a clinician.
What should I do if I get diarrhea on a trip?
The NHS says drink lots of fluids to avoid dehydration, and seek urgent advice for bloody diarrhea or diarrhea lasting more than 7 days. [1]
Does yogurt prevent traveler's diarrhea?
Proper evidence not found in the sources we read for yogurt or fermented foods preventing traveler's diarrhea; supplement results do not transfer to foods. [4]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety points before a trip
- Weak immunity or serious illness. NCCIH says risk of harm from probiotics is greater in people with severe illnesses or compromised immune systems. [2] Ask before using any, including yeast-based products: see Saccharomyces boulardii and Probiotic Safety.
- Medicines. Tell your clinician or pharmacist about every probiotic, particularly if you take immunosuppressants or antibiotics: see Probiotics and Medicine Interactions. Never stop a prescribed medicine because of a supplement.
- Product quality while abroad. Buying unfamiliar products abroad adds quality and labelling uncertainty; NCCIH reports products with organisms not on the label. [2] See Probiotic Label Accuracy.
- Children and babies. Children's use is covered on Probiotics for Children and Teens.
- Do not use a probiotic as a reason to put off care. NCCIH advises talking with a health care provider and not postponing care. [2]
References
- NHS (UK). Diarrhoea and vomiting. Read 2026-10-23.
- NCCIH (US National Center for Complementary and Integrative Health). Probiotics: Usefulness and Safety. Read 2026-10-23.
- Meta-analysis of probiotics for the prevention of traveler's diarrhea. Travel Med Infect Dis 2007. PubMed 17298915 (abstract). Read 2026-10-23.
- Are probiotics and prebiotics effective in the prevention of travellers' diarrhea: a systematic review and meta-analysis. Travel Med Infect Dis 2019. PubMed 30278238 (abstract). Read 2026-10-23.
- Bismuth subsalicylate, probiotics, rifaximin and vaccines for the prevention of travelers' diarrhea: a systematic review and network meta-analysis. Front Pharmacol 2024. PubMed 38698820 (abstract). Read 2026-10-23.
- Riddle MS et al. Guidelines for the prevention and treatment of travelers' diarrhea: a graded expert panel report (International Society of Travel Medicine). J Travel Med 2017. PubMed 28521004 (abstract). Read 2026-10-23.