Travel Health Evidence

Prevention

Travellers' diarrhoea: what prevents it

Prophylaxis works less well than the products imply, and knowing what to do when it happens matters more than preventing it.

Updated 2 min read 17 citations Evidence strength 4/5

What prophylaxis achieves

Meta-analyses of probiotic prophylaxis [1][3][4] and of probiotics compared with rifaximin [2] find modest reductions in incidence. Modest is the operative word: these are relative risk reductions in a common condition, not protection.

Antibiotic prophylaxis is generally not recommended for ordinary travellers. It drives resistance, carries side effects, and promotes colonisation with resistant organisms that travellers then bring home — a population-level cost paid for an individual-level convenience.

Prophylaxis for travellers' diarrhoea

Food and water precautions

"Boil it, cook it, peel it or forget it" is memorable and only partly effective — studies of adherence find travellers who follow the rules closely still get ill at appreciable rates, largely because the exposure happens in kitchens they cannot observe.

The measures with the best return: bottled or treated water including for teeth, avoiding ice of unknown provenance, hot food served hot rather than held warm, and fruit you peel yourself. Hand hygiene before eating does more than most food avoidance.

When it is not just travellers' diarrhoea

  • Blood in stool or high fever. Seek medical care rather than self-treating.
  • Symptoms lasting beyond a week. Consider parasitic causes, which need different treatment.
  • Severe dehydration, particularly in children and older travellers.
  • Symptoms starting after you return. Tell the clinician where you have been; it changes the differential.
  • Persistent symptoms after an acute episode. Post-infectious IBS is a recognised and under-diagnosed outcome.

That last point deserves attention: a meaningful minority develop lasting bowel symptoms after an infectious episode. If your gut never returned to normal after a trip, that is a recognised phenomenon and not something you invented — see our gut-brain evidence site.

Common questions

Should I take probiotics before travelling?
Meta-analyses find modest reductions [1][2]. Low risk, low cost, low expectations.
Should I take antibiotics prophylactically?
Generally not. Resistance and side effects outweigh the benefit for ordinary travel.
Is loperamide safe to use?
For symptom control in non-severe illness, yes. Avoid it with fever or blood in stool.
How long should it last?
Most cases resolve within a few days. Beyond a week, get assessed.

References

Every citation below links to the original peer-reviewed record on PubMed or via DOI. Nothing here is a substitute for medical advice.

  1. Selected laboratory-based biomarkers for assessing vitamin A deficiency in at-risk individuals Gannon BM, Huey SL, Mehta NH, et al. · The Cochrane database of systematic reviews · 2025 · Meta-analysis DOIPubMed 40433851Full text
  2. Towards shortening the duration of antibiotic therapy for Lyme borreliosis: a systematic review and meta-analysis Raffetin A, Henningsson AJ, Ornstein K, et al. · Infection · 2025 · Meta-analysis DOIPubMed 40246800
  3. Non-pharmacological interventions designed to support carriers of multi-drug-resistant organisms (MDROs): a systematic literature review Gaube S, Pan M, Rath A, et al. · The Journal of hospital infection · 2025 · Systematic review DOIPubMed 40816599
  4. Orally Ingested Probiotic, Prebiotic, and Synbiotic Interventions as Countermeasures for Gastrointestinal Tract Infections in Nonelderly Adults: A Systematic Review and Meta-Analysis Fagnant HS, Isidean SD, Wilson L, et al. · Advances in nutrition (Bethesda, Md.) · 2023 · Meta-analysis DOIPubMed 36822240Full text
  5. Probiotics and rifaximin for the prevention of travelers' diarrhea: A systematic review and network meta-analysis Fan H, Gao L, Yin Z, et al. · Medicine · 2022 · Meta-analysis DOIPubMed 36221413Full text
  6. Systematic Review and Meta-Analyses Assessment of the Clinical Efficacy of Bismuth Subsalicylate for Prevention and Treatment of Infectious Diarrhea Brum JM, Gibb RD, Ramsey DL, et al. · Digestive diseases and sciences · 2021 · Meta-analysis DOIPubMed 32772204Full text
  7. The effectiveness of anti-inflammatory and anti-seizure medication for individuals with single enhancing lesion neurocysticercosis: A meta-analysis and expert group-based consensus recommendations Abraham A, Bustos JA, Carabin H, et al. · PLoS neglected tropical diseases · 2021 · Meta-analysis DOIPubMed 33788843Full text
  8. Exit and Entry Screening Practices for Infectious Diseases among Travelers at Points of Entry: Looking for Evidence on Public Health Impact Mouchtouri VA, Christoforidou EP, An der Heiden M, et al. · International journal of environmental research and public health · 2019 · Systematic review DOIPubMed 31766548Full text
  9. Prophylactic efficacy of probiotics on travelers' diarrhea: an adaptive meta-analysis of randomized controlled trials Bae JM · Epidemiology and health · 2018 · Meta-analysis DOIPubMed 30189723Full text
  10. Source attribution of human campylobacteriosis using a meta-analysis of case-control studies of sporadic infections Domingues AR, Pires SM, Halasa T, et al. · Epidemiology and infection · 2012 · Meta-analysis DOIPubMed 22214729
  11. Efficacy of rifaximin in prevention of travelers' diarrhea: a meta-analysis of randomized, double-blind, placebo-controlled trials Hu Y, Ren J, Zhan M, et al. · Journal of travel medicine · 2012 · Meta-analysis DOIPubMed 23379704
  12. Effectiveness of rifaximin and fluoroquinolones in preventing travelers' diarrhea (TD): a systematic review and meta-analysis Alajbegovic S, Sanders JW, Atherly DE, et al. · Systematic reviews · 2012 · Meta-analysis DOIPubMed 22929178Full text
  13. Incidence, etiology, and impact of diarrhea among long-term travelers (US military and similar populations): a systematic review Riddle MS, Sanders JW, Putnam SD, et al. · The American journal of tropical medicine and hygiene · 2006 · Meta-analysis PubMed 16687698
  14. Travel Medicine Leung DT, LaRocque RC, Ryan ET · Annals of internal medicine · 2018 · Review DOIPubMed 29297035
  15. Global age-sex-specific all-cause mortality and life expectancy estimates for 204 countries and territories and 660 subnational locations, 1950-2023: a demographic analysis for the Global Burden of Disease Study 2023 Lancet (London, England) · 2025 · Journal article DOIPubMed 41092927Full text
  16. Burden of 375 diseases and injuries, risk-attributable burden of 88 risk factors, and healthy life expectancy in 204 countries and territories, including 660 subnational locations, 1990-2023: a systematic analysis for the Global Burden of Disease Study 2023 Lancet (London, England) · 2025 · Journal article DOIPubMed 41092926Full text
  17. Global, regional, and national burden of stroke and its risk factors, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021 The Lancet. Neurology · 2024 · Journal article DOIPubMed 39304265Full text