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Dr. Chrysoula I. Liakou MD, PhD
- Treated online: Yes, usually. Short-lived diarrhoea is assessed by video, with rehydration advice, anti-sickness medicine where vomiting blocks fluids, loperamide where it is safe, and stool tests or antibiotics arranged when the picture calls for them; blood, high fever, severe pain or dehydration signs need in-person care.
- What it is: loose or watery stools 3 or more times a day; viruses (norovirus, rotavirus) cause most short-lived diarrhoea, bacteria (Campylobacter, Salmonella, E. coli) and parasites (Giardia) the rest, and adults have about 1 episode a year on average.
- How long: viral diarrhoea settles in 5 to 7 days and vomiting in 1 to 2 days, traveller's diarrhoea in 3 to 5 days; diarrhoea beyond 2 weeks needs a stool test, and beyond 4 weeks a search for IBS, coeliac disease, IBD or a medicine.
- Fluids first: oral rehydration solution from a pharmacy replaces salts as well as water and is the evidence-backed choice; small frequent sips beat large drinks, and plain starchy food can be eaten as soon as it is tolerated.
- Contagion: assume you can pass a gut infection on while symptomatic and for 48 hours after the last episode, so stay home until then and wash hands with soap and water: alcohol gel is weak against norovirus.
- Emergency: call 112 for diarrhoea with confusion or drowsiness, fainting, a rigid painful abdomen, or heavy bleeding, and get in-person care for black tar-like stools, high persistent fever, or passing little or no urine.
Get in-person care, rather than a video appointment, if there is blood in your stools or they are black and tar-like, you have a high persistent fever or severe abdominal pain, or there are signs of serious dehydration: drowsiness or confusion, passing little or no urine, cold hands and feet, or feeling faint whenever you stand. Call 112 for confusion, fainting or a rigid painful abdomen. Babies, frail older adults and pregnant women dehydrate faster; err on the side of urgent review.
Can an online doctor treat diarrhoea?
Yes, in most cases. On Mobi Doctor, a licensed doctor assesses diarrhoea by video: onset, travel and food history, fluid balance and red flags. Most episodes are viral and need structured rehydration rather than medication, and the doctor tells you that honestly; blood, high fever or serious dehydration is routed to in-person care.[1]
Diarrhoea suits video assessment because the decisions hang on history and hydration, both assessable on a call: what came first, who else is unwell, where you have been, what you can keep down, and how much urine you are passing. The honest limits are examination and testing: a tender abdomen needs hands, and persistent or bloody diarrhoea needs stool samples, which the doctor arranges through local services rather than pretending a camera can replace them.
Listen: Diarrhoea Treatment Online
The audio version of this topic from the Mobi Doctor podcast. Open the episode.
How an online consultation helps with diarrhoea
- A proper dehydration check: the doctor walks through the markers that matter (urine output and colour, thirst, dizziness on standing, drowsiness) and identifies who is high-risk, because dehydration, not the diarrhoea itself, is what makes this illness dangerous.[1]
- Honest prescribing: most diarrhoea needs no antibiotic, and you will be told so plainly; where a specific bacterial or parasitic infection is likely, targeted treatment follows testing or a careful clinical case, not habit.
- Medicines managed while you are unwell: some regular medicines, including blood pressure tablets, diuretics and metformin, may need a short pause during significant dehydration, and the doctor tells you which and for how long, coordinating with your regular prescriber where needed.
- Wherever you are in Europe: ill in a hotel in Lisbon or an apartment in Kraków, the assessment works the same way, in English, with a plan matched to what is available locally.
What the doctor checks in an online diarrhoea consultation
The story usually names the cause, so the consultation is built around it. The doctor will typically ask about:
- Onset and course: hours or days, sudden or creeping, improving or worsening, and how many stools a day at the worst.
- What the stools look like: watery, fatty, with mucus, or with blood, and whether black and tar-like, which changes everything.
- Vomiting and fluid balance: whether you can keep sips down, roughly what you have drunk today, and your urine output and colour, the practical dehydration gauge.
- Fever: how high, how persistent, and whether with shivering.
- Travel: where and when, because destination changes the likely organisms and whether parasites belong on the list.
- Food and contacts: suspect meals, and whether household members or fellow travellers are ill too, the outbreak pattern of norovirus and food poisoning.[5]
- Recent antibiotics or hospital care: diarrhoea after a course of antibiotics raises C. difficile, which needs testing rather than guessing.
- Your background: inflammatory bowel disease, diabetes, kidney disease, immunosuppression and pregnancy all lower the threshold for review.
- Your job: food handlers, carers and healthcare workers need specific advice about staying off work until 48 hours after the last episode.[2]
What causes diarrhoea?
Most acute diarrhoea is caused by gut infections, viruses above all, spread through contaminated food, water and close contact; bacteria such as Campylobacter and Salmonella, and parasites such as Giardia, account for a smaller share, more after travel. Medicines, especially antibiotics, are a common non-infectious cause, and diarrhoea lasting over 4 weeks has a different list altogether.[1]
Infections: the big three groups
Viral gastroenteritis is the everyday version: sudden watery diarrhoea, often with vomiting and cramps, sweeping through households and settling within about a week. Bacterial causes, typically from food, are likelier when fever runs higher, pain is more marked or blood appears. Parasites enter the picture with travel and with symptoms that grumble on for weeks rather than days: Giardia, classically, brings prolonged watery diarrhoea, bloating and remarkable wind after a trip. The treatment implications differ, which is why the history earns its keep.
Medicines and other non-infectious causes
Antibiotics themselves loosen stools in a sizeable minority of people, usually mildly, occasionally seriously (C. difficile). Metformin, some blood pressure treatments, proton pump inhibitors, magnesium antacids and overdone sugar-free sweeteners all cause diarrhoea; so does overshooting laxatives. When diarrhoea alternates with constipation over months, with cramping and bloating, the pattern points towards irritable bowel syndrome; when it persists beyond 4 weeks, or carries weight loss, night symptoms or a family history of bowel disease, it needs a structured work-up with stool tests, blood tests and sometimes referral, rather than another round of self-treatment.
How do I know if I am dehydrated?
Early dehydration shows as thirst, a dry mouth, headache, tiredness and darker, scantier urine; feeling light-headed when you stand is a step further. Serious dehydration shows as drowsiness or confusion, passing little or no urine, cold mottled hands and feet, and a racing heart, and it needs urgent in-person care, not monitoring at home.[1]
Rehydrating properly is a technique, not just a volume: frequent small sips beat occasional large glasses, which tend to come straight back up. Oral rehydration solution from any pharmacy replaces salts as well as water and is the evidence-backed choice, for adults as well as children; the WHO credits oral rehydration with saving millions of lives, which is a striking pedigree for a sachet.[1] Keep eating as tolerated once vomiting settles, plain food first. Alcohol and large caffeine hits work against you. For babies, frail older adults and anyone whose illness is into its third day without improvement, the threshold for medical review drops sharply.
What helps traveller’s diarrhoea?
Traveller’s diarrhoea is usually caused by bacteria picked up from food or water in an unfamiliar place, and most episodes settle within 3–5 days with fluids and rest. Oral rehydration solution is the foundation; loperamide can cover an essential travel day but should be avoided with blood in the stool or high fever. Routine antibiotics are not recommended.[3]
The stewardship point matters more each year: reflex antibiotic use for every loose stool abroad drives resistance and disrupts your own gut flora, and international guidance reserves standby antibiotics for specific higher-risk situations, such as remote travel with underlying illness, decided with a doctor in advance rather than improvised from a hotel room.[3][4] What a video consultation adds mid-trip is judgement: whether yours is the ordinary self-limiting kind, whether anything needs testing or treating where you are, and which local red flags should send you to in-person care. Prevention is simple and effective: bottled or treated water where tap water is unsafe, food served hot, fruit you peel yourself, and hand hygiene before eating. If symptoms begin towards the end of a trip and persist after you return, say so at assessment, because post-travel diarrhoea that lingers is exactly where parasite testing pays off.
Is my diarrhoea suitable for online care?
Most diarrhoea is, at least for assessment. Here is how doctors sort it, and where in-person care takes over.
Swipe sideways to compare →
| Diarrhoea presentation | Likely first step | Suitable for online care? | When referral or in-person care is needed |
|---|---|---|---|
| Watery diarrhoea for a few days, no blood, drinking well | Fluids, oral rehydration solution and rest; loperamide where suitable[2] | Usually yes, often without a prescription | Lasting more than about a week, or any red flag appearing |
| Traveller’s diarrhoea while abroad in Europe | Rehydration plan, symptom care and targeted advice[3] | Usually yes | Blood in stool, high fever, or not improving after about 3 days |
| Diarrhoea after a recent antibiotic course or hospital stay | Assessment and stool testing for C. difficile | Assessment yes; testing in person | Marked pain, fever or profuse diarrhoea: prompt in-person care |
| Diarrhoea lasting more than 4 weeks | Structured work-up: stool tests, blood tests, referral where needed[2] | Assessment yes; tests in person | Weight loss, bleeding, night-time symptoms, or family history of bowel disease |
| Blood in stool, high fever, severe pain or serious dehydration signs | In-person or emergency care | No | Same day; call 112 for confusion, fainting or a rigid abdomen |
Not sure if yours needs more than fluids? A doctor can tell you in one consultation.
See available times →Treatment options for diarrhoea
What you can do yourself
Rehydration is the treatment: small frequent sips, oral rehydration solution by preference, and eating as tolerated once vomiting settles rather than starving yourself, which delays recovery. Loperamide is reasonable for adults who need to function through an essential day, at the labelled dose, but not with blood in the stool or high fever, and not for children. Protect the household: wash hands with soap and water (alcohol gel is weak against norovirus), separate towels, clean shared surfaces, and stay home until 48 hours after the last episode, longer rules applying to food handlers.[2] Probiotics are optional: evidence is mixed, harm is unlikely, and no one should feel obliged.
Prescription treatment
A prescription is never issued without a consultation, and for diarrhoea the honest headline is that most episodes need none. Where vomiting blocks rehydration, an anti-sickness medicine can break the cycle. Antibiotics are only prescribed when there are signs of a specific bacterial or parasitic infection, guided by stool testing or a careful clinical picture such as dysentery-type illness or confirmed Giardia after travel; they do not help viral gastroenteritis, and unnecessary courses drive antibiotic resistance for everyone.[4] The consultation also covers your regular medicines, pausing the ones that turn dehydration into kidney trouble, and ends with a written safety net: what should improve by when, and exactly which changes mean escalate.
When diarrhoea is treated online, and when you need in-person care
Treated online: acute watery diarrhoea in otherwise well adults, with a rehydration plan and review point; traveller’s diarrhoea anywhere in Europe, including standby planning before higher-risk trips; medication-related diarrhoea, adjusted with your regular prescriber; and persistent change work-ups started properly: stool tests ordered through local services, results reviewed, referral where they point onwards.
In-person care: blood in the stool, black stools, high persistent fever or severe pain, to in-person care the same day; serious dehydration signs, drowsiness, confusion, little or no urine, to emergency care with 112 named; suspected C. difficile with marked symptoms, promptly in person; babies and frail older adults with significant losses, to hands-on assessment early, because they decompensate fast; and diarrhoea beyond 4 weeks with weight loss, bleeding or night symptoms, to gastroenterology with the referral letter written during your consultation.
When to get in-person care
Go to emergency care now for diarrhoea with drowsiness or confusion, little or no urine passed, blood in the stool with faintness, a high fever with shivering, or severe constant abdominal pain with a rigid or very tender belly. If someone becomes confused, cannot stay awake or collapses, call 112 immediately. Babies and frail older adults with ongoing losses need urgent review, not watchful waiting.
How Mobi Doctor works
- Book a time that suits you: open daily 7am–11pm CET. You can see a doctor over video, usually within 15 minutes. No subscription, exact price up front.
- Speak to a licensed doctor about diarrhoea: a private video call: you describe what you feel, the doctor asks what matters, and you agree the right plan together.
- Leave with your plan: everything agreed before you hang up: your plan, and a prescription to use at a pharmacy near you where medication is clinically right for you. If your doctor decides you need to be seen in person, you get a full refund.
No sign-up needed
Diarrhoea can have more than one cause. Tick every symptom you have to see each condition page that mentions it. It finds the right page, not a diagnosis: a doctor gives you that on a video call.
Tap the body — an area or a point — to browse symptoms anywhere
Similar symptoms, different condition? Gastroenteritis can start the same way. Compare them, or look up any other symptom in the full symptom checker.
Frequently asked questions about diarrhoea
What causes diarrhoea?
Most short-lived diarrhoea is caused by a gut infection: viruses such as norovirus and rotavirus, bacteria such as Campylobacter, Salmonella and E. coli from food or water, or parasites such as Giardia after travel. Other causes are food intolerance, anxiety, alcohol, medicines including antibiotics, metformin, laxatives and magnesium antacids, and, when diarrhoea persists for weeks, irritable bowel syndrome, coeliac disease, inflammatory bowel disease, an overactive thyroid or bile acid malabsorption.
Can an online doctor prescribe antibiotics for diarrhoea in Europe?
Only when the assessment points to a specific bacterial or parasitic infection, usually guided by stool testing, because antibiotics do not work against the viruses behind most diarrhoea and unnecessary courses drive resistance and can worsen some infections. A prescription is never issued without a consultation; rehydration advice, anti-sickness medicine and loperamide where safe can be arranged the same consultation.
When should I worry about diarrhoea?
Worry about diarrhoea when there is blood in the stool or stools turn black, fever is high and persistent, pain is severe or constant, or dehydration signs appear: drowsiness, confusion, little or no urine, or fainting on standing. Also take seriously diarrhoea lasting beyond two weeks, diarrhoea after recent antibiotics or hospital care, and diarrhoea in anyone frail, pregnant or immunosuppressed.
What should I eat and drink with diarrhoea?
Drink small frequent sips, ideally oral rehydration solution from a pharmacy, which replaces salts as well as water; diluted squash or soup are second best, and fizzy drinks, fruit juice and alcohol make diarrhoea worse. Once vomiting settles, eat as you can manage: plain starchy food such as rice, toast, potatoes and bananas first, building back to normal over a day or two. Starving yourself slows recovery.
Is it safe to take loperamide for diarrhoea?
For most otherwise-well adults with watery diarrhoea, yes, at the labelled dose, and it can make an essential travel or work day manageable. Avoid loperamide if there is blood in the stool, a high fever or severe pain, because slowing the bowel can worsen some bacterial infections, and do not use it for children. It treats the symptom, not the cause, so fluids still come first.
How long does diarrhoea picked up abroad last?
Most episodes of traveller's diarrhoea settle within three to five days with fluids, rest and oral rehydration solution, and loperamide can cover a journey. See a doctor sooner, wherever you are, for blood in the stool, high fever, signs of dehydration, or no improvement after about three days, when a short antibiotic course may be right; diarrhoea that grumbles on for weeks after travel is tested for Giardia.
When do I need a stool test for diarrhoea?
A stool test is worthwhile when diarrhoea is bloody, severe or persistent beyond about a week, after recent antibiotics or hospital care, after travel where parasites are plausible, during an outbreak, or when you are immunosuppressed or work in food handling or healthcare. Testing identifies the organisms that change treatment, such as Campylobacter, Giardia or Clostridioides difficile, and the online doctor can arrange it.
How long am I contagious after diarrhoea?
Assume you can pass on a gut infection while symptomatic and for about 48 hours after the last episode of diarrhoea or vomiting, which is why the standard advice is to stay away from work, school or nursery until that window has passed. Food handlers, healthcare workers and carers wait the full 48 hours, and some infections such as norovirus shed for days longer, so hand washing continues.
How long does diarrhoea last?
Viral diarrhoea usually stops within five to seven days and vomiting within one to two days; bacterial food poisoning lasts two to seven days; traveller's diarrhoea three to five days. Diarrhoea beyond two weeks is persistent and needs a stool test, and diarrhoea beyond four weeks is chronic, which points to irritable bowel syndrome, coeliac disease, inflammatory bowel disease, a medicine or bile acid malabsorption rather than an infection.
How do I know if I am dehydrated?
Dehydration from diarrhoea shows as thirst, a dry mouth, dark urine or passing little urine, tiredness, dizziness on standing and a headache; serious dehydration adds drowsiness or confusion, a racing heart, cold hands and feet, sunken eyes and fainting, and needs in-person care. Weighing yourself, counting trips to the toilet and checking urine colour are the simplest home checks, especially for older people.
What can I do at home for diarrhoea?
At home, rest, sip oral rehydration solution after every loose stool, eat plain food when hungry, take paracetamol for aches and fever, use loperamide only if there is no blood or fever, keep to your own towel, wash hands with soap after every toilet visit, clean the bathroom with bleach-based cleaner, and stay off work for 48 hours after the last episode. Probiotics shorten some diarrhoea by about a day.
How can I prevent diarrhoea?
Prevent infectious diarrhoea by washing hands with soap before eating and after the toilet, cooking meat and eggs through, keeping raw and cooked food apart, refrigerating leftovers quickly, drinking bottled or treated water and avoiding ice, salads and undercooked food in high-risk countries, and staying home when ill so it does not spread. Reviewing medicines and limiting sweeteners, alcohol and caffeine prevent much non-infectious diarrhoea.
Is diarrhoea different in pregnancy or in older people?
In pregnancy, diarrhoea is usually a gut infection and is managed with fluids and rest; loperamide is generally avoided, and persistent diarrhoea or fever is reviewed promptly because dehydration can trigger contractions. In older people, dehydration sets in faster and shows as confusion or falls, medicines are a commoner cause, and Clostridioides difficile after antibiotics is a particular concern, so the threshold for in-person review is lower.
- Diarrhoeal disease fact sheet, WHO, World Health Organization, 2024.
- Diarrhoea (adults): assessment, Clinical Knowledge Summary, NICE, National Institute for Health and Care Excellence, revised 2023.
- Gastroenteritis: Clinical Knowledge Summary, NICE, National Institute for Health and Care Excellence, revised 2024.
- Antimicrobial resistance, ECDC, European Centre for Disease Prevention and Control, 2023.
- Food poisoning, HSE, Health Service Executive (Ireland), accessed August 2026.
- Diarrhoea and vomiting, NHS, National Health Service (UK), reviewed December 2023.
This page is for information only and is not a substitute for a medical consultation. Guideline links are provided for transparency; treatment decisions are made with your doctor.
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