How Long Is a Stomach Bug Contagious? The 48-Hour Rule

A stomach bug is contagious for as long as you are being sick or have diarrhoea, and for at least 48 hours after the last episode. That is why the NHS, the CDC and Spanish paediatricians all say to stay off work, school or nursery for 2 days after symptoms stop. The CDC says norovirus can still spread for 2 weeks or more, so careful handwashing still matters.

Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).

For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.

How long is a stomach bug contagious?

You can pass it on from the moment you feel ill. You are most contagious while you are vomiting or have diarrhoea. That is when the most virus leaves your body.

After you feel better, the risk drops but does not vanish. The CDC says you can still spread norovirus for 2 weeks or more after you feel better.

That is why health services use a simple rule: stay away from others until 48 hours after the last episode. Then keep washing your hands well for the next couple of weeks.

How long does a stomach bug last?

Usually not long. The NHS says vomiting tends to stop within 1 or 2 days. Diarrhoea usually stops within 5 to 7 days, in adults and children.

• Norovirus: starts suddenly, 12 to 48 hours after contact. Most people feel better within 1 to 3 days.
• Rotavirus: the main cause in babies and young children. Mayo Clinic notes that adults with rotavirus may have no symptoms and still pass it on. Spain's national vaccine schedule now includes a rotavirus vaccine for babies from 6 weeks of age.
• Food poisoning: comes from the food itself. Some cases are caused by the same viruses. Our guide on food poisoning and stomach bugs in Spain covers telling them apart.

Some people also get a fever, a headache, tummy pain or aching muscles. You can catch norovirus more than once. The CDC explains that there are many types, and one infection may not protect you from the next.

When can I go back to work or school?

Wait until you have had no vomiting and no diarrhoea for at least 48 hours. The advice is the same in the UK, the US and Spain:

• The NHS says to stay off school or work for 2 days after symptoms stop.
• The CDC says to wait at least 48 hours, above all if you work with food, in schools or in care.
• The Spanish Paediatrics Association (AEP) says children should not go back to school or nursery until 48 hours after symptoms stop.

The NHS also says to stay out of swimming pools for 48 hours after the last episode. Do not visit people in hospital or in a care home until then either.

If you handle food at work, do not prepare food for others while sick. Check your employer's rules before you go back, as some are stricter.

How do I stop it spreading at home?

Norovirus is very easy to catch and hard to kill. These steps help:

• Wash your hands with soap and water. Do it after the toilet or a nappy change, and before you eat or cook. The NHS says alcohol gel does not kill norovirus.
• Do not cook for others while you are sick, if you can avoid it.
• Clean up vomit and diarrhoea with gloves. The CDC advises a bleach-based cleaner left on the area for at least 5 minutes. Then wash it again with hot, soapy water.
• Wash soiled clothes and bedding on their own, on a hot wash. The NHS says 60°C.
• Clean the bathroom daily: toilet seat, flush handle, taps and door handles.
• Do not share towels, flannels, cutlery or cups.

What helps while you recover?

There is no cure for a viral stomach bug. Your body clears it. The main job is to keep fluids in.

• Take small sips often. Water, or an oral rehydration solution from a pharmacy, works well. In Spain, ask for suero oral.
• Eat when you feel ready. The AEP advises against strict or "binding" diets for children.
• Keep breastfeeding or bottle feeding babies. Do not make formula weaker, says the NHS.
• Rest at home and stay away from others while you are ill.

Ask a pharmacist or a doctor before you take anything to stop diarrhoea. This matters most for children and if there is blood or a fever.

When should I see a doctor?

See a doctor today, without waiting, if:

• You cannot keep fluids down.
• You show signs of dehydration: little or dark pee, dizziness, a dry mouth.
• A baby under 12 months is ill, or a child stops feeding.
• A child under 5 has fewer wet nappies than usual.
• There is blood in the diarrhoea, or bleeding from the bottom.
• Vomiting lasts more than 2 days, or diarrhoea more than 7 days.
• You are pregnant, older, or have a weak immune system and feel very unwell.

Call 112 or go to urgencias if you or your child:

• Vomit blood, or vomit that looks like coffee grounds.
• Have green vomit.
• Have a stiff neck and pain when looking at bright lights.
• Have a sudden, severe headache or a sudden, severe tummy ache.
• Have blue, grey, pale or blotchy skin, lips or tongue.
• Struggle to breathe, or are confused or not responding as usual.
• May have swallowed something poisonous.

Talking it through with a doctor by video

Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:

• Ask when it started, how often you are sick and what you can keep down.
• Look for signs of dehydration on camera.
• Explain when you can go back to work, school or nursery.
• Tell you if you need to be seen in person, and where.

He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.

A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.

This guide is general information. It does not replace a consultation with your doctor.

Frequently asked questions

Sources

• NHS: Diarrhoea and vomiting
• NHS: Norovirus
• CDC: About norovirus
• CDC: Preventing norovirus
• Mayo Clinic: Viral gastroenteritis (stomach flu)

Related guides

• Food poisoning and stomach bugs in Spain
• Travellers' diarrhoea: planning before a trip
• How long a cold lasts and when it is contagious
• Flu symptoms and how long flu lasts
• Diarrhoea and vomiting care by video
• Abdominal pain consultation