Stomach Bug, Food Poisoning or Gastroenteritis? What to Do, How Long It Lasts and When to See a Doctor
Vomiting and diarrhoea are usually caused by a stomach bug, most often norovirus in the winter months, or by food poisoning, and most people get better on their own. According to the NHS, diarrhoea usually stops within 5 to 7 days and vomiting within 1 or 2 days. The main risk is dehydration, which is why fluids matter more than anything else, especially for babies, older people and anyone with a long-term condition. Antibiotics are rarely needed, because most stomach bugs are caused by viruses. You should stay off work or school until 48 hours after the last episode of vomiting or diarrhoea, because you can still spread the infection. Some symptoms need a doctor the same day, including blood in your stools, signs of dehydration such as passing little urine or feeling dizzy on standing, vomiting that stops you keeping fluids down, severe abdominal pain, diarrhoea lasting more than 7 days, and symptoms after recent travel abroad, which may need a stool test. At The Wellness video consultations start from £150 and home visits cost £450. Enquire for clinic appointments and confirm availability, suitability for a fit note and any separate costs. Fees appear further down this page.
Reviewed by the medical team at The Wellness. Last updated 10 October 2026.
See a doctor today on WhatsApp or email team@thewellnesslondon.com or call 020 3951 3429.
Key facts about stomach bugs
- Vomiting usually stops within 1 or 2 days and diarrhoea within 5 to 7 days.
- Dehydration is the main risk, so sip fluids often, including oral rehydration solution.
- Antibiotics are rarely needed, because most stomach bugs are viral.
- Stay off work or school until 48 hours after your last episode.
- Blood in the stools, dehydration, severe pain or symptoms after travel need a doctor.
Is it a stomach bug or food poisoning
A stomach bug, or viral gastroenteritis, spreads from person to person and through contaminated surfaces. Norovirus is the commonest cause in adults and is most common in winter. It usually starts suddenly with nausea and vomiting, followed by diarrhoea, and often affects several people in a household.
Food poisoning is caused by eating food contaminated with bacteria, viruses or toxins. Symptoms can start within hours or several days after eating, depending on the cause, and may affect others who ate the same food.
The treatment for both is usually the same. A doctor will look for features that suggest a bacterial infection, a complication or another cause.
How to look after yourself
Drink small amounts often. Water, diluted squash and oral rehydration solution, available from pharmacies, replace lost fluid and salts. Oral rehydration solution is especially useful for older people and anyone with a long-term condition.
Eat when you feel able. There is no need to avoid food, and plain food is often easiest to start with.
Rest, and use paracetamol for pain or fever if suitable for you.
Wash your hands with soap and water, as alcohol gel does not kill norovirus, and do not prepare food for others while unwell.
Ask a doctor about your symptoms on WhatsApp or email team@thewellnesslondon.com.
What are the signs of dehydration
Passing little urine, or dark, strong-smelling urine. Feeling dizzy or light-headed, especially when standing. A dry mouth, lips and eyes. Feeling very tired or confused.
In babies and young children, look for fewer wet nappies, a sunken soft spot on the head, few or no tears when crying, and drowsiness. Children become dehydrated more quickly than adults.
When to see a doctor the same day
Blood in your stools, or black, tarry stools.
Signs of dehydration that are not improving with fluids, or vomiting that stops you keeping any fluids down.
Severe or constant abdominal pain, particularly if it is in one place.
Diarrhoea lasting more than 7 days, or vomiting lasting more than 2 days.
Symptoms after travel abroad, which may need a stool test for infections such as campylobacter, salmonella or parasites.
Symptoms in someone who is pregnant, older, has a weakened immune system, diabetes or kidney disease.
When to call 999 or go to A&E
Call 999 for vomiting blood or material that looks like coffee grounds, a very drowsy or confused person, severe abdominal pain with a rigid, tender abdomen, or signs of severe dehydration such as not passing urine all day.
Do you need to stay off work
Yes. Stay off work or school until 48 hours after the last episode of vomiting or diarrhoea, because you can still spread the infection during this time. People who handle food, work in healthcare or care for vulnerable people should follow this carefully.
You can self-certify sickness for up to 7 days. After that, your employer can ask for a fit note from a doctor.
What does it cost to see a private doctor for a stomach bug in London
Fees depend on the type of consultation, examination, tests and treatment needed. Confirm the full cost before booking.
Confirm the consultation scope, total fee and any separate prescription, medicine, fit note, vaccine or test costs before booking.
- Platinum and Signature Membership: enquire for current scope, access terms and fees.
- Home visit £450. Hotel visit £495 daytime or £595 evening. Enquire for additional household members, office, weekend and out-of-area fees.
- Blood panel with consultation for persistent symptoms: enquire for clinical suitability, scope and fees.
- In-person consultation with examination: enquire for scope, availability and fees.
- Video consultation from £150. Confirm availability, suitability for a fit note and any separate costs.
Appointments are available 7 days a week by video, at our London clinics, including Marylebone and Belgravia, or at home.
Why patients choose The Wellness for stomach bugs
Because you can be seen today without leaving home, when travelling is the last thing you can manage.
Because a doctor checks for dehydration and the warning signs that need more than rest.
Because stool tests and blood tests are arranged when symptoms persist or follow travel.
Because the whole household can be seen in one visit.
Fit notes and prescriptions depend on assessment. Confirm their availability and any separate costs before booking.
Related reading
Bloating, IBS and reflux covers longer-term gut symptoms, bowel and gut health screening covers persistent changes, flu, COVID or a cold covers winter viruses, private GP home visits covers doctors who come to you, and private sick note and fit note covers time off work.
Book a same-day appointment on WhatsApp or call 020 3951 3429.
Frequently asked questions
How long does a stomach bug last
Vomiting usually stops within 1 or 2 days and diarrhoea within 5 to 7 days, according to the NHS.
How long should I stay off work with diarrhoea and vomiting
Stay off work or school until 48 hours after the last episode of vomiting or diarrhoea, because you can still spread the infection.
Do I need antibiotics for food poisoning
Usually not. Most stomach bugs and many cases of food poisoning settle on their own, and antibiotics do not help viral infections. A doctor may arrange a stool test and consider treatment if symptoms are severe, persistent or follow travel.
When should I see a doctor about diarrhoea
If there is blood in your stools, you are dehydrated, you have severe abdominal pain, diarrhoea lasts more than 7 days, symptoms follow travel abroad, or you are pregnant, older or have a long-term condition.
What should I drink when I have a stomach bug
Small, frequent sips of water, diluted squash or oral rehydration solution, which replaces lost salts and is especially useful for older people and those with long-term conditions.
How much does a private doctor cost for a stomach bug in London
At The Wellness video consultations start from £150 and home visits cost £450. Enquire for clinic appointments, additional household members and any separate prescription, medicine, fit note or test costs.
The Wellness is a doctor-led private healthcare group providing medical care from our London clinics, including Marylebone and Belgravia. All doctors are GMC-registered. Prescriptions are issued only following a consultation and clinical assessment. In an emergency call 999. This article is general information and not a substitute for medical advice about your own health.
Enquire now on WhatsApp or email team@thewellnesslondon.com or call 020 3951 3429.
References
Blood Tests
Doctor-led panels from single markers to full screens, read and explained the same day.
View Blood TestsRelated Services
Request a consultation or test with The Wellness