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Dr. Chrysoula I. Liakou MD, PhD
- Treated online: Yes, usually. Gastroenteritis is assessed by video, with a fluid plan, anti-sickness medicine where vomiting stops fluids staying down, and advice on which medicines to pause; blood in the stool, high fever or inability to keep fluid down need in-person care.
- What it is: infection of the gut lining by norovirus (the commonest cause in adults, 12 to 48 hours after contact), rotavirus or adenovirus in children, or bacteria such as Campylobacter and Salmonella from food; adults average about 1 episode a year and young children 2 to 3.
- How long: vomiting usually settles within 1 to 2 days and diarrhoea within 3 to 7; vomiting beyond 2 days, diarrhoea beyond 7, or any red flag sooner is the point for a doctor, and diarrhoea beyond 2 weeks needs a stool test.
- Dehydration: the main danger of gastroenteritis, above all in babies, older adults and pregnant women; thirst, dark or scanty urine, dizziness and a dry mouth are early signs, and drowsiness, confusion, sunken eyes or cold hands mean urgent care.
- Spread: gastroenteritis spreads by hands, surfaces and vomit droplets and a person stays infectious for 48 hours after the last episode; soap and water removes norovirus far better than alcohol gel, and bleach-based cleaner is needed for surfaces.
- Emergency: call 112 if someone with gastroenteritis is confused, floppy or hard to wake, cannot keep any fluid down and is passing no urine, has a rigid painful abdomen, or is vomiting blood.
A baby or small child who is drowsy, has sunken eyes, dry nappies, no tears or cold hands and feet needs urgent in-person care, not a video call. The same urgency applies to any age with blood in the stool, a high fever that will not settle, or inability to keep any fluid down. If someone is confused, floppy or hard to wake, call 112 now.
Can an online doctor treat gastroenteritis?
Yes, for most cases. Gastroenteritis, the classic stomach bug with vomiting and diarrhoea, is usually viral and self-limiting, so treatment centres on preventing dehydration rather than on medicines.[1] On Mobi Doctor, a licensed doctor assesses hydration on camera, builds a recovery plan, and prescribes where assessment supports it. Children with dehydration signs, blood in the stool or a patient who cannot drink need in-person care.
There is also an infection-control argument for staying on your sofa: stomach bugs are ferociously contagious, and a waiting room is the perfect place to donate yours to a dozen strangers.
Listen: Gastroenteritis Treatment Online
The audio version of this topic from the Mobi Doctor podcast. Open the episode.
How an online consultation helps with gastroenteritis
- Dehydration checked properly: the doctor walks through urine output, thirst and dizziness, and tells you clearly which side of the line you are on.[4]
- A fluid plan by age: how much, how often, and when plain water is not enough: oral rehydration salts for children, older adults and heavy losses, in small frequent sips that stay down.
- Medicines paused before they bite: diuretics, some blood-pressure tablets and metformin can turn a routine stomach bug into kidney trouble while you are dry. The doctor tells you what to stop and when to restart.
- Household damage control: practical isolation and hygiene rules that actually stop the spread, plus the 48-hour rule for returning to school, work and food handling.[1]
What the doctor checks in an online gastroenteritis consultation
The consultation is built around one question, how dry are you and how fast are you drying out, plus a screen for the cases that are not simple viral illness. The doctor will typically establish:
- Losses versus intake: how often you are vomiting and passing stool, what you have managed to drink and keep down in the last six hours.
- Hydration signs on camera: for adults, urine colour and frequency, dizziness on standing, dry mouth; for children, alertness, sunken eyes, tears when crying, wet nappies, and how the child looks and behaves on screen.[4]
- Who is ill: age (under 5s and over 65s carry the highest risk), pregnancy, immune suppression, kidney disease, diabetes, and frailty.
- The exposure story: household or workplace outbreaks, nursery contacts, a suspect meal, recent travel, recent antibiotics (which raises a different, treatable cause of diarrhoea).
- Regular medicines: which need pausing during fluid loss, and which make dehydration more dangerous.
- Red flags: blood or mucus in the stool, high persistent fever, severe localised pain, confusion, no urine for many hours, symptoms beyond a week.
What causes gastroenteritis?
Viruses cause the large majority of cases. Norovirus leads in adults and causes the explosive winter outbreaks that empty offices and cruise ships; rotavirus historically led in young children, though vaccination has cut its impact across much of Europe.[3] Bacteria such as campylobacter and salmonella account for a smaller share, usually foodborne, and parasites are rarer again, mostly after travel. The practical point cuts through the microbiology: whatever the organism, the illness usually looks the same and the first-line treatment, fluids and time, is identical.[1][2]
Is it gastroenteritis, norovirus or food poisoning?
These three labels overlap, and sorting them takes one sentence each. Gastroenteritis is the umbrella term for gut infection with vomiting and diarrhoea, whatever the cause. Norovirus is the single commonest virus behind it, spreading person to person with dramatic speed. Food poisoning is gastroenteritis you caught from what you ate rather than from someone infectious.
The label changes the follow-up more than the treatment. If your illness marched through the household one person at a time, it behaves like norovirus, and the norovirus page covers the outbreak-control side. If it arrived hours after a suspect meal, or several people who shared food went down together, the foodborne angle, stool tests and reporting are covered on the food poisoning page. And if loose stools are the whole story, without much vomiting, start at the diarrhoea page, because longer-running diarrhoea has its own list of causes worth ruling out.
When should I worry about dehydration?
Worry when fluid stops going in or stops staying in. The warning signs are passing little or no urine, dizziness on standing, drowsiness or confusion, and in children: sunken eyes, no tears, dry nappies, unusual sleepiness or fast breathing. These signs mean same-day medical review, in person where they are marked.[4]
Children first
Small children dehydrate fastest because their reserves are smallest and their losses, per kilo, are biggest. Vomiting alone for more than a day, refusal to drink, or any of the signs above should lower your threshold to seek care to the floor. Oral rehydration solution given as frequent small sips (a syringe or spoon works when a cup is refused) is the evidence-based home treatment; fizzy drinks and undiluted juice make diarrhoea worse.[2][4]
Older adults and the medicines problem
In older people, dehydration often announces itself as confusion, unsteadiness or a fall rather than thirst. The stakes are raised by everyday prescriptions: diuretics and certain blood-pressure medicines keep pulling fluid and salt out of a body that is already losing both, and metformin becomes riskier as the kidneys dry. This is the single most useful reason for an older person with a stomach bug to speak to a doctor early: a two-minute medicine review can prevent the complication that would have caused a hospital admission.
Do I need antibiotics for gastroenteritis?
Almost never. Most gastroenteritis is viral, and antibiotics do nothing against viruses; they are only prescribed when there are signs of a specific bacterial infection where treatment helps, because unnecessary courses cause side effects and fuel antibiotic resistance.[1] Even most bacterial cases clear on their own, and in some (notably certain E. coli infections) antibiotics can make complications more likely rather than less. The exceptions, severe illness, immunosuppressed patients, specific organisms confirmed on stool testing, are exactly what the consultation screens for. An honest doctor treats the fluid problem first and reserves the prescription pad for the cases that need it.
Is my gastroenteritis suitable for online care?
Usually yes, with predictable exceptions. This is the decision framework the doctors use, aligned with the cited guidance.
Swipe sideways to compare →
| Presentation | Likely first step | Suitable for online care? | When referral or in-person care is needed |
|---|---|---|---|
| Adult with vomiting and diarrhoea, drinking and passing urine | Fluid-first plan, hygiene rules, safety-netting | Usually yes | Red flags appear, or no improvement after about 48 hours |
| Child who is alert, drinking, with wet nappies | Oral rehydration solution in frequent small sips[4] | Often yes, with clear escalation rules | Any dehydration sign, blood in stool, or a baby under 6 months |
| Older adult, or anyone on diuretics, blood-pressure tablets or metformin | Early review with medicine-pause plan | Usually yes, seen promptly | Confusion, falls, very low urine output, or kidney concerns |
| Blood in stool, high persistent fever, or recent travel outside Europe | Assessment plus stool testing pathway[1] | For triage and organising tests | In-person review if unwell or worsening |
| Cannot keep any fluid down, confusion, drowsiness, no urine | Emergency care | No | Call 112 immediately |
Not sure which row is you? A doctor can tell you in one consultation.
See available times →Treatment options for gastroenteritis
What you can do yourself
Drink small amounts often; large gulps come straight back. Oral rehydration salts from any pharmacy are the gold standard for children, older adults and anyone with heavy losses, because they replace salts and sugar in the proportions the gut absorbs best.[2][5] Eat when appetite returns, keeping it small and bland at first; there is no evidence that starving shortens the illness. Rest, and stay home until 48 hours after the last episode of vomiting or diarrhoea, the standard exclusion window for work, school and nursery, applied strictly to food handlers and carers.[1] At home, soap and hot water beat alcohol gel against norovirus, and towels stop being communal property until everyone is clear.
Prescription treatment
A prescription is never issued without a consultation. Where assessment supports it, the doctor can prescribe an anti-sickness medicine so fluids stay down, advise on loperamide for adults who must function (never with blood in the stool or high fever, and not for young children), organise stool testing for the presentations that warrant it, and prescribe antibiotics only in the narrow circumstances described above.
When gastroenteritis is treated online, and when you need in-person care
Treated online: typical stomach bugs in adults who are alert and drinking; hydration plans with clear escalation rules; medicine-pause reviews for older and chronically ill patients; anti-sickness treatment where appropriate; stool-test organisation for travel-related or prolonged cases; and return-to-work and outbreak-hygiene advice.
In-person care: babies under 6 months with vomiting and diarrhoea, and any child with dehydration signs, go to in-person care the same day;[4] blood in the stool or persistent high fever needs examination and testing; anyone who cannot keep fluids down despite treatment needs assessment for intravenous rehydration; and diarrhoea that has run past two weeks stops being gastroenteritis and starts being a work-up, which the doctor arranges. If your doctor decides you need to be seen in person, you get a full refund and clear directions to the right care.
When to get in-person care
Seek same-day in-person care for blood in the stool, high fever that will not settle, dehydration signs in a child (sunken eyes, dry nappies, no tears, drowsiness), or an older person who becomes confused or unsteady. Call 112 immediately if someone cannot be roused, is floppy or limp, has cold mottled skin, or has passed no urine for many hours despite trying to drink.
Is gastroenteritis contagious?
Very, especially the norovirus kind. It spreads through hands, surfaces, shared bathrooms and food handled while ill, and it is famously efficient in households, offices and cruise ships.
The 48-hour rule: stay home until 48 hours after the last episode of vomiting or diarrhoea, strictly so for food handlers, carers and healthcare workers.
Protecting your household: soap and water over alcohol gel, which is weak against norovirus, separate towels, and disinfecting bathroom surfaces while anyone is ill.
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 gastroenteritis: a private video call: you describe what you feel, the doctor asks what matters, and you agree the right plan together.
- Get your fluid plan and escalation rules: 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
Not sure it’s gastroenteritis? 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? Diarrhoea can start the same way. Compare them, or look up any other symptom in the full symptom checker.
Frequently asked questions about gastroenteritis
What is gastroenteritis, and what causes it?
Gastroenteritis is inflammation of the stomach and intestines caused by an infection, and it produces vomiting, diarrhoea, cramps and sometimes fever. In adults the usual cause is norovirus, caught from an infected person, contaminated surfaces or food; in children rotavirus and adenovirus; and in both, bacteria such as Campylobacter, Salmonella and E. coli from food or water, or parasites such as Giardia after travel. Antibiotics taken recently can also trigger it.
What are the symptoms of gastroenteritis?
Gastroenteritis starts suddenly with nausea and vomiting, often projectile with norovirus, then watery diarrhoea, cramping abdominal pain, loss of appetite, aching muscles, headache and sometimes a mild fever and chills. Symptoms peak in the first day or two and fade over the week. Blood in the stool, a high persistent fever or severe constant pain are not typical of viral gastroenteritis and need assessment.
Can an online doctor prescribe medicine for gastroenteritis in Europe?
Yes, where assessment supports it: typically anti-sickness medicine to help fluids stay down, and advice on pausing medicines such as diuretics, blood-pressure tablets or metformin while you are losing fluid. Antibiotics are rarely appropriate for gastroenteritis, because most of it is viral, and are prescribed only after a stool test points to a bacterial cause that needs them. A prescription is never issued without a consultation.
How long does gastroenteritis last?
Vomiting usually settles within one to two days; diarrhoea commonly lasts three to seven days, sometimes a little longer in children. Adults improving within that window rarely need tests. See a doctor if vomiting passes two days, diarrhoea passes a week, or any red flag appears sooner, and expect tiredness and a sensitive stomach for a week after the gastroenteritis itself has gone.
What should I give a child with a stomach bug to drink?
Oral rehydration solution from a pharmacy, offered as small frequent sips, by spoon or syringe if a cup is refused, after every vomit or loose stool. Continue breastfeeding or formula as normal. Avoid fizzy drinks, undiluted fruit juice and sports drinks, which draw water into the gut and worsen diarrhoea. Mobi Doctor sees adults only, so a child with gastroenteritis who is drowsy, has dry nappies or sunken eyes needs in-person care.
When can my child go back to school or nursery after gastroenteritis?
Forty-eight hours after the last episode of vomiting or diarrhoea. Earlier return is the engine of nursery outbreaks, because children remain infectious while they feel better. The same 48-hour rule applies to adults returning to work, and strictly so for food handlers, healthcare workers and carers, and swimming pools should be avoided for two weeks after gastroenteritis caused by Cryptosporidium.
Is gastroenteritis the same as food poisoning?
They overlap. Gastroenteritis is the umbrella term for gut infections causing vomiting and diarrhoea; food poisoning is the subset caught from contaminated food rather than from an infected person. Symptoms and treatment are largely identical, so the label matters mainly for tracing the source: several people ill after one meal points to food, illness spreading through a household over days points to a virus.
How do I know if gastroenteritis is causing dehydration?
Early dehydration shows as thirst, a dry mouth, dark or little urine, headache, tiredness and dizziness on standing. Serious dehydration shows as drowsiness or confusion, a racing heart, cold hands and feet, sunken eyes, no urine for eight hours, and in babies a sunken soft spot, no tears and dry nappies; that stage of gastroenteritis needs in-person or emergency care, not a video call.
What can I do at home for gastroenteritis?
At home, with gastroenteritis, rest, sip oral rehydration solution little and often, eat plain food such as toast or rice as soon as you feel able, take paracetamol for fever and aches, use your own towel, wash hands with soap and water after every toilet visit and before touching food, clean the toilet, flush handle, taps and surfaces with a bleach-based cleaner daily, and stay home for 48 hours after the last episode.
How can I prevent gastroenteritis?
Prevent gastroenteritis by washing hands with soap and water after the toilet, before preparing food and after caring for someone ill, cleaning vomit and surfaces with bleach-based products, washing soiled laundry hot, not sharing towels, cooking food through and chilling leftovers, drinking safe water when travelling, and keeping an ill person away from food preparation and from work or nursery for 48 hours.
Is gastroenteritis contagious?
Very. Norovirus gastroenteritis spreads through tiny amounts of vomit or stool on hands, surfaces, food and droplets, a few virus particles are enough, and a person is infectious from the first symptoms until at least 48 hours after the last episode, with some shedding for days longer. Hand washing with soap, bleach cleaning and staying home are what stop it; alcohol gel alone is not enough.
Is gastroenteritis more serious in pregnancy, in older people or with other illnesses?
Yes. In pregnancy, gastroenteritis is usually harmless to the baby, but dehydration can bring on contractions, so fluids are replaced carefully and fever is reviewed promptly. In older people, dehydration arrives faster, shows as confusion or falls, and diuretics or blood-pressure tablets may need pausing. People with diabetes, kidney disease, inflammatory bowel disease or a weakened immune system are assessed early rather than watched.
- Gastroenteritis: Clinical Knowledge Summary, NICE, National Institute for Health and Care Excellence, 2023.
- Diarrhoeal disease fact sheet, WHO, World Health Organization, 2024.
- Norovirus infection, ECDC, European Centre for Disease Prevention and Control, 2024.
- Diarrhoea and vomiting caused by gastroenteritis in under 5s (CG84), NICE, National Institute for Health and Care Excellence, 2009.
- Reduced osmolarity oral rehydration solution for treating dehydration caused by acute diarrhoea in children (Cochrane Review), Cochrane, Cochrane Collaboration, accessed August 2026.
- Dehydration, NHS, National Health Service (UK), reviewed May 2026.
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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