What counts as traveller's diarrhoea
The clinical definition is at least three loose or watery stools in 24 hours, usually starting within the first two weeks of travel. In practice you know it when you have it: stomach cramps, urgent bathroom trips, a few loose stools, and a general sense that the holiday has paused.
Most cases are caused by bacteria picked up from food or water. Some are viral. In southern Europe, including Spain, the food safety standards are generally high and the most common triggers are not "bad water" but lapses on holiday — unwashed salad, undercooked seafood, ice in drinks at less reputable bars, or just the gut adjusting to a different diet and a different routine.
Symptoms typically peak within 24 to 48 hours and resolve within three to five days. Mild cases need no medication at all, only fluids and rest.
When to head straight to a hospital
Some patterns signal something more serious than ordinary traveller's diarrhoea. Do not wait for an online consultation in any of the following.
- Blood or mucus in the stools, beyond a trace
- A fever above 38.5°C, particularly with shivering or feeling severely unwell
- Severe abdominal pain that is not relieved by going to the toilet
- Signs of significant dehydration — dizziness on standing, very dark urine, no urine for eight hours, sunken eyes, or in children, no tears when crying
- Persistent vomiting for more than 24 hours, particularly if you cannot keep fluids down
- Symptoms lasting more than seven days without improvement
- You are pregnant
- You are immunocompromised — on chemotherapy, immunosuppressive treatment, or with significant chronic illness
- The affected person is a young child or an older adult who looks dehydrated or confused
For any combination of severe dehydration, collapse, or confusion, call 112. The Holiday Doctor cannot help with these cases, and the form will say so immediately at no charge.
Hydration is the single most important thing
Whatever else you do or don't do, replacing fluid and salt lost to diarrhoea is the treatment. Most people with mild-to-moderate traveller's diarrhoea recover entirely on hydration alone.
The most effective fluid is oral rehydration solution — sold in Spanish pharmacies as suero oral or under various brand names. It contains the exact salt and sugar mix the gut absorbs best when it is irritated. Sip it through the day, not in large gulps. As a rough guide, aim to replace each loose stool with around 250ml of fluid and keep your urine pale.
Water, weak tea, broth, and diluted fruit juice all help. Pure water alone is less effective because it lacks salt. Sports drinks are an imperfect substitute — too much sugar, not enough salt — but better than nothing if you cannot get to a pharmacy. Avoid alcohol and strong coffee until you are recovered.
What a Spanish pharmacy can do without a prescription
Spanish farmacias are well stocked for travel-related stomach trouble. Without a prescription they will offer:
- Oral rehydration salts — the most important thing in the pharmacy bag.
- Anti-motility medication (loperamide), which reduces the number of bathroom trips and helps you function for a day. Useful for travel days. Not appropriate when there is blood in the stools or a high fever.
- Probiotics, which have a modest evidence base for shortening the illness by half a day or so.
- Activated charcoal, frequently sold for "gas and bloating", less useful for the diarrhoea itself.
- Paracetamol for any aches and low-grade fever. Avoid ibuprofen until you are clearly improving — it can irritate an already irritated gut.
For mild-to-moderate cases, this is often enough. Antibiotics are prescription-only in Spain and cannot be bought over the counter, and pharmacies cannot supply them without a valid receta.
When antibiotics are appropriate
Most travellers do not need antibiotics. Hydration and time do the job. Antibiotics shorten the duration of the illness by about a day on average, with the benefit concentrated in moderate-to-severe cases — the ones with a high fever, blood in the stools, or symptoms severe enough to disrupt the trip.
The decision to use an antibiotic depends on how severe the symptoms are, how long they have been going on, what red flags are present or absent, and your personal history. That is a clinical decision and it sits inside the consultation, not on a web page. There are also good reasons not to use antibiotics in mild cases — they can prolong some infections, and overuse is a real public health problem.
How to get a Spanish prescription the same day
Three routes, the same as for any non-urgent prescription need in Spain.
Public route: Centro de Salud
With an EHIC, a UK GHIC, or a Spanish tarjeta sanitaria, any Centro de Salud will see you. For diarrhoea this is the right route if you are seriously unwell or have any of the red flags above — they can examine you, take samples, and put up a drip if you need it.
Private in-person GP
A private GP appointment costs EUR 50 to 120, usually same-day. English-speaking clinicians are common. You leave with a Spanish receta privada.
Online private consultation
For uncomplicated moderate diarrhoea in an otherwise well adult — no fever above 38.5°C, no blood, no warning signs — an online consultation can collect the relevant history quickly, our doctor can follow up by phone or email if anything needs clarifying, and a prescription can be issued the same day if appropriate.
The Holiday Doctor flow: complete the form (about five minutes), our doctor reviews it the same day within consultation hours (9am to 7pm Monday to Friday, 12pm to 6pm Saturday and Sunday), often with a short call or email. If a prescription is appropriate, it is issued through REMPe and collectable at any Spanish pharmacy.
What to do for the rest of the trip
Most cases settle quickly. The practical advice for the next few days:
- Keep drinking. Oral rehydration solution if you can get it, plain fluids if not. Keep urine pale.
- Eat what you can tolerate. The old "BRAT" guidance (bananas, rice, apple sauce, toast) is fine but not strict — anything bland and starchy that you can keep down is useful. Reintroduce normal food gradually.
- Avoid further triggers — undercooked seafood, salad of uncertain origin, ice in drinks at venues you wouldn't normally trust.
- Wash your hands before eating and after going to the toilet, every time. Diarrhoea spreads easily between travellers.
- Stay out of pools and the sea until you have had no diarrhoea for 48 hours.
- If you have started antibiotics, finish the full course even if you feel better.
- Watch for new red flags — high fever, blood, severe pain, dehydration — and seek in-person care if any appear.
Important. The Holiday Doctor does not assess severe or complicated diarrhoea, diarrhoea in pregnancy, in young children, or any of the situations listed above. If there is any possibility your situation is an emergency, call 112.