Traveller's diarrhoea — prevention, treatment and stand-by antibiotics

The reality

Around one in three travellers to high-risk regions develops some form of traveller's diarrhoea. Most cases are mild and self-limiting — 24 to 72 hours of discomfort, then recovery. A meaningful minority become more serious, especially in children, the elderly, those with chronic illness, and travellers a long way from medical care.

The right approach is two-layered: sensible prevention to reduce risk, and a well-stocked travel kit to manage what does happen. Both are within reach of a 20-minute travel consultation.

Prevention — food and water rules that actually work

The classic advice ("boil it, cook it, peel it, or forget it") still applies. The practical translation:

• Water. Bottled or properly purified water for drinking and brushing teeth. Avoid tap water in high-risk destinations. Check the bottle seal is intact.
• Ice. Same problem as tap water — avoid unless you know the source.
• Hot food. Freshly cooked, served hot, in places with high turnover. Buffets sitting at ambient temperature are higher risk.
• Fruit. Whole fruit you peel yourself (bananas, oranges). Pre-cut fruit is higher risk.
• Salads and raw vegetables. Higher risk because of washing water quality.
• Unpasteurised dairy. Higher risk; pasteurised products generally fine.
• Street food. Often fine if busy with high turnover and food clearly cooked through. Quiet, slow-turnover stalls are higher risk.
• Seafood. Particularly raw or partially cooked seafood; higher risk especially in warm coastal areas.
• Hand hygiene. Soap and water before eating, after toilet. Alcohol gel useful as backup.

Rules that don't reliably work: a 'small sip' of unsafe water, the assumption that boiled-then-cooled water is safe (often re-contaminated), expensive restaurants being inherently safer (often aren't).

Food and water in different scenarios

• Tourist hotel. Generally lower risk but not zero. The buffet at the end of breakfast is one of the higher-risk locations even in 5-star hotels.
• VFR (visiting friends and relatives). Home-cooked food by family is usually safer than street food but not zero-risk — water source and hand hygiene of the cook matter. See our destination guides for India, Bangladesh, and Pakistan for VFR-specific food and water tips.
• Backpacker / budget travel. Higher exposure to unsafe water; ORS, water purification tablets or a SteriPEN, and stand-by antibiotic discussion all become more relevant.
• Safari and remote travel. Distance from medical care raises the bar for self-treatment readiness.

Oral rehydration — the single most useful thing

Most deaths from diarrhoea worldwide are from dehydration, not the diarrhoea itself. Oral rehydration salts (ORS) prevent and treat this effectively. Practical points:

• Carry several sachets in your travel kit. They're cheap, light, and have a long shelf life.
• Mix per packet instructions — typically one sachet in 200–250 ml of safe water.
• Drink small frequent amounts (more easily tolerated than large gulps).
• Continue eating something bland as soon as you can tolerate it — rice, toast, bananas, plain biscuits. The old 'starve a stomach' advice is outdated.
• Continue breastfeeding infants who develop diarrhoea — don't stop.

If ORS isn't available, plain rehydration with safe water works less well but is better than nothing. Avoid plain water alone in significant diarrhoea — you need the electrolytes ORS contains.

Loperamide — when it helps, when it doesn't

Loperamide (Imodium) reduces stool frequency by slowing gut motility. It's safe and useful for short-term adult use in mild traveller's diarrhoea — particularly useful for journeys, flights, or important events.

Appropriate use:

• Mild diarrhoea in adults without fever or blood.
• Bridging through travel days or important events.
• Symptom relief alongside hydration.

When not to use it:

• Fever or blood in stool (slowing the gut retains infected material).
• Severe abdominal pain.
• Children under 12 (different products for paediatric use).
• Inflammatory bowel disease or other gut conditions — check with clinician.

Stand-by antibiotics — the conversation worth having

For some travellers, a 'stand-by' course of antibiotics (typically azithromycin or ciprofloxacin, depending on destination) is prescribed for self-treatment of moderate-to-severe diarrhoea while abroad. The aim is to shorten illness duration in scenarios where reaching medical care quickly might be difficult.

When stand-by antibiotics are usually appropriate:

• Travel to high-risk destinations.
• Travel to remote areas without easy access to medical care.
• Travellers with significant chronic illness where prolonged diarrhoea would be a bigger risk.
• Trips where work or travel commitments make extended illness costly.
• Pregnant women in some scenarios (drug choice differs).

When stand-by antibiotics aren't usually appropriate:

• Short-stay tourist trips to areas with good medical access.
• Trips where you'd realistically just rest and seek care.
• Some patients with specific medical contraindications.

How to use them correctly:

• Only start if symptoms are moderate to severe (not for mild illness — fluids alone usually suffice).
• Take the full short course as prescribed.
• Continue hydration alongside.
• Seek medical care if symptoms don't improve in 24–48 hours, or if red flags develop.

Antibiotic choice depends on destination (regional resistance patterns vary), your medical history, and current pregnancy or other circumstances. Azithromycin is commonly first-line in Asia given ciprofloxacin resistance in Campylobacter; ciprofloxacin is still appropriate for many other destinations. Antibiotic stewardship matters — don't use stand-by courses for mild illness or non-diarrhoea purposes.

Probiotics — limited evidence but generally harmless

Some travellers ask about probiotics for prevention. The evidence base is mixed and modest at best — some studies show a small reduction in traveller's diarrhoea, others show no effect. They're generally harmless and you can take them if you want to, but they're not a substitute for sensible food and water choices.

Children

Children, particularly under 5, are at higher risk of significant dehydration from diarrhoea. Practical advice:

• ORS is the priority — keep offering small amounts frequently.
• Continue breastfeeding infants.
• Don't use loperamide in children.
• Lower threshold for seeking medical care — fever in a small child with diarrhoea needs assessment.
• Watch for signs of dehydration: dry mouth, no tears when crying, fewer wet nappies, sunken fontanelle, drowsiness.

When to seek medical care abroad

Red flags meaning don't wait it out:

• High fever (above 38.5°C).
• Blood in stool.
• Severe abdominal pain.
• Signs of moderate or severe dehydration (dark urine, low urine output, dizziness on standing, confusion).
• Symptoms lasting more than 3 days.
• Severe vomiting preventing fluid intake.
• Any concerning symptoms in pregnant women, infants, elderly, or those with significant chronic illness.
• Symptoms that get worse after a brief improvement (could suggest Giardia or parasitic causes).

When you get home

If diarrhoea persists beyond 14 days after returning home, see your GP — longer-lasting illness may indicate Giardia, Cryptosporidium, or another parasitic cause that needs specific treatment. Also see your GP if you develop new symptoms (fever, jaundice, weight loss) within weeks of returning from a high-risk area — some travel infections can present later.

What to put in your travel kit

The realistic minimum:

• Oral rehydration salts (several sachets).
• Loperamide (Imodium) for adults.
• Paracetamol and/or ibuprofen for fever and pain.
• Antiseptic wipes or alcohol gel.
• Plasters, basic dressings.
• Sunscreen (SPF 30+) and insect repellent (DEET-based, 20–50%).
• If prescribed: stand-by antibiotic course.
• Any regular medication in original packaging — see our prescription medication travel guide.

How this fits with the wider travel prep

Diarrhoea prevention is part of a broader travel health picture. Other relevant guides: India, Bangladesh, Pakistan, East Africa, malaria tablets compared, Yellow Fever certificate, travel insurance with pre-existing conditions.

The next step

If you'd like a travel consultation that includes stand-by antibiotic discussion, a kit list specific to your trip, and any vaccines you need, the next step is a 20–30 minute consultation. We can prescribe and dispense stand-by antibiotics on the same visit for eligible travellers.