Vomiting and diarrhoea are common in children and are usually caused by a stomach bug. Most children recover at home within a few days, but dehydration can happen quickly, especially in babies and younger children. The key is knowing how to give fluids, what to avoid, and when symptoms need urgent medical advice.
Few childhood illnesses disrupt family life quite like vomiting and diarrhoea. A child may suddenly go from seeming well to being sick repeatedly, having loose stools, refusing food and lying on the sofa looking pale and exhausted. For parents and carers, the worry is not only the mess and sleepless night. It is the question underneath it all: is this just a tummy bug, or something more serious?
Most vomiting and diarrhoea in children is caused by viral gastroenteritis, often called a stomach bug. Norovirus and rotavirus are common examples. These infections spread easily through hands, surfaces, food, toys, towels and close contact, which is why they often move quickly through nurseries, schools and households.
In many cases, vomiting settles within 1 to 2 days and diarrhoea improves over several days. The most important treatment is not a special diet or medicine. It is preventing dehydration by giving regular fluids in small amounts.
This guide explains what to do at home, how to spot dehydration, when to call NHS 111, when to seek urgent help, and when your child can return to school or nursery. You can also find more parent health guides in our Children’s Health section.
What counts as vomiting and diarrhoea?
Vomiting means your child is being sick and bringing up stomach contents. It is different from a baby posseting small amounts of milk after feeds, which is common and usually harmless if the baby is otherwise well and gaining weight.
Diarrhoea means your child’s poo is looser or more watery than usual, and they are usually going more often. Some babies normally have soft or runny nappies, especially breastfed babies, so the important change is what is unusual for your child.
Vomiting and diarrhoea often happen together, but they can also happen separately. A child may start with vomiting, then develop diarrhoea later. They may also have tummy cramps, mild fever, headache, aching limbs, tiredness and reduced appetite.
What usually causes vomiting and diarrhoea in children?
The most common cause is a viral stomach infection. These infections usually get better on their own and do not need antibiotics. Antibiotics only treat bacterial infections, and they will not help an ordinary viral tummy bug.
Vomiting and diarrhoea can also be caused by food poisoning, travel-related infection, food intolerance, a reaction to medicine, anxiety, migraine, or another infection elsewhere in the body. Younger children may vomit when they have a high temperature, bad cough, ear infection, urine infection or chest infection.
Sometimes vomiting is not “just a bug”. Severe tummy pain, a swollen abdomen, green vomit, blood in vomit or stool, persistent drowsiness, a stiff neck, a non-fading rash or signs of dehydration all need medical attention.
If your child also has a cough, cold symptoms or fever, you may find our guides to coughs and colds in children and fever in children useful.
The main risk: dehydration
The biggest concern with vomiting and diarrhoea is dehydration. Children lose fluid and salts when they are sick or have watery stools. Babies and young children have smaller reserves, so they can become dehydrated more quickly than adults.
Early dehydration can be subtle. Your child may be more tired than usual, have a dry mouth, seem thirsty, pass less urine, or have fewer wet nappies. Their urine may look darker or smell stronger. They may cry with fewer tears.
More worrying signs include sunken eyes, a sunken soft spot on a baby’s head, cold hands and feet, unusual drowsiness, fast breathing, mottled or blotchy skin, dizziness, confusion, or no urine for many hours. A child who is becoming difficult to wake, floppy, very irritable or unable to keep down any fluids needs urgent medical help.
We have a separate guide to dehydration symptoms in adults and children, which is worth reading if your child is losing fluids or drinking less than usual.
How to give fluids when your child keeps vomiting
When a child vomits repeatedly, it is tempting to offer a full cup of water as soon as they ask for a drink. Unfortunately, large amounts can stretch the stomach and trigger more vomiting. Small, frequent sips usually work better.
Start with tiny amounts. For younger children, this may mean a teaspoon or syringe of fluid every few minutes. Older children can take small sips often. If they vomit, pause for a few minutes and then start again slowly. Many children can absorb some fluid even if they are still being sick occasionally.
Breastfed babies should continue breastfeeding. They may want shorter, more frequent feeds. Formula-fed babies should usually continue their normal formula at the normal strength. Do not water down formula unless a healthcare professional has specifically told you to.
Oral rehydration solution, often called ORS, can be useful if your child is at risk of dehydration or already showing mild signs. It contains a careful balance of salts and sugar to help the body absorb fluid. ORS sachets are available from pharmacies. Follow the instructions exactly when mixing them.
The NHS advises that diarrhoea and vomiting can usually be treated at home, with fluids being the most important treatment to avoid dehydration. You can read the NHS overview of diarrhoea and vomiting for further official advice.
What should children drink?
For many children, water, breast milk, usual formula feeds and oral rehydration solution are the main options. Small amounts often are better than large drinks.
Avoid fizzy drinks and fruit juice while diarrhoea is ongoing, as they can make diarrhoea worse. Sports drinks are not designed for young children with gastroenteritis and do not replace ORS. If your child refuses ORS, speak to a pharmacist, GP or NHS 111 for advice rather than forcing it.
Ice lollies can help some children take fluid slowly, but they should not replace proper rehydration if your child is dehydrated. The goal is steady fluid intake and regular urine or wet nappies.
Should children eat when they have vomiting and diarrhoea?
Do not worry if your child does not want much food for a short time. Appetite often disappears during a tummy bug. Drinking is more important than eating in the first day or two.
When your child wants food, offer simple, familiar meals. Toast, rice, pasta, potatoes, soup, yoghurt, bananas, crackers or their normal foods are all reasonable if they can tolerate them. There is usually no need for a very restricted “BRAT” diet. Let appetite guide you and return gradually to normal eating.
Avoid forcing food. A child who is pushed to eat before they are ready may vomit again. It is fine to offer small portions and try again later.
Can children take medicine for vomiting or diarrhoea?
Most children do not need medicine to stop vomiting or diarrhoea. Anti-diarrhoeal medicines, sometimes called antimotility medicines, are generally not recommended for children unless a doctor specifically advises them. They can be unsafe in some situations and may make certain infections worse.
Do not give aspirin to children under 16 unless it has been prescribed by a doctor.
Children’s paracetamol may help if your child is uncomfortable or has a fever, but it will not treat the stomach bug itself. If your child vomits soon after taking medicine, ask a pharmacist or NHS 111 what to do rather than immediately repeating the dose, as the advice may depend on timing and the medicine.
Ibuprofen can sometimes irritate the stomach and may not be suitable if your child is dehydrated or not drinking well. If your child has a fever as well as vomiting or diarrhoea, read our guide to fever in children or ask a pharmacist for advice.
When vomiting is more worrying
Vomiting is common with tummy bugs, but certain patterns need urgent attention.
Seek urgent medical help if your child has green vomit, blood in their vomit, severe or worsening tummy pain, a swollen or hard tummy, signs of meningitis such as a stiff neck or dislike of bright lights, a seizure, a non-blanching rash, or is very drowsy, floppy or confused.
Vomiting after a head injury should also be taken seriously, especially if it happens repeatedly or is accompanied by drowsiness, confusion, severe headache, unusual behaviour, poor balance or a seizure.
In babies, repeated forceful vomiting, poor feeding, fewer wet nappies, a swollen tummy, green vomit or a baby who seems very sleepy or floppy should be assessed urgently.
When diarrhoea is more worrying
Watery diarrhoea is common with viral gastroenteritis, but blood or mucus in the stool, severe tummy pain, persistent fever, signs of dehydration, or diarrhoea that does not improve should prompt medical advice.
You should also seek advice if your child has recently travelled abroad, has a weakened immune system, has an existing medical condition, or is a young baby. Diarrhoea in very young babies can become serious more quickly because they dehydrate faster.
If your child has diarrhoea after taking antibiotics, contact your GP or NHS 111, especially if symptoms are severe, persistent or there is blood in the stool.
When to call NHS 111, your GP or 999
Call 999 or go to A&E now if your child is very difficult to wake, floppy, confused, struggling to breathe, has blue lips, has a seizure, has a stiff neck, has a rash that does not fade when pressed with a glass, has green vomit, has severe constant tummy pain, or you think they are seriously unwell.
Contact your GP or call NHS 111 urgently if your child cannot keep down fluids, has signs of dehydration, has blood in their poo, has repeated vomiting, has diarrhoea many times in a day, has a fever that is not settling, has symptoms lasting longer than expected, or is under 6 months old and you are concerned.
Healthier Together provides a useful parent-friendly traffic-light approach for diarrhoea and vomiting in children under 5. It is especially helpful when deciding whether symptoms are mild, need same-day advice, or need urgent care.
Trust your instincts
If your child looks seriously unwell, seek help. You do not need to wait for every red flag to appear before contacting NHS 111, your GP or emergency services.
How long does a stomach bug last?
Vomiting often improves within 24 to 48 hours. Diarrhoea can last longer, sometimes several days. Some children have looser stools for a week or more while the gut recovers.
Your child should gradually become brighter, drink more and pass urine more normally. If they are getting worse rather than better, if vomiting continues repeatedly, if diarrhoea is severe or bloody, or if they are showing signs of dehydration, seek medical advice.
A lingering reduced appetite is common after a tummy bug. However, weight loss, persistent tummy pain, ongoing diarrhoea, blood in the stool or symptoms that keep returning should be discussed with a GP.
Should my child stay off school or nursery?
Yes. Children with diarrhoea and/or vomiting should stay away from school, nursery and childcare while they are unwell. They should not return until 48 hours after the last episode of diarrhoea or vomiting.
This 48-hour rule matters because stomach bugs spread very easily, and children can still be infectious after symptoms begin to settle. UKHSA guidance for education and childcare settings advises that children with diarrhoea and vomiting should stay away until 2 days after symptoms have stopped. You can read the official UKHSA health protection guidance for schools and childcare settings.
Your child should also feel well enough to take part in normal activities before returning. If they are still exhausted, not eating or drinking normally, or needing frequent toilet trips, they need more time at home.
Can my child go swimming after diarrhoea?
It is best to avoid swimming while your child has diarrhoea and for a period afterwards, because some infections can spread through swimming pools. For certain infections, such as cryptosporidium, exclusion from swimming may need to be longer. If your child has had confirmed or suspected cryptosporidium, follow public health or GP advice.
How to stop it spreading at home
Stomach bugs spread easily, especially in homes with young children. Handwashing with soap and water is one of the most important steps. Alcohol hand gel is not as reliable for some stomach bugs, including norovirus, so soap and water matters.
Clean toilet seats, flush handles, taps, door handles, light switches and changing mats regularly. Wash soiled clothes, towels and bedding promptly. Do not share towels. If possible, give the unwell child their own towel and encourage everyone in the household to wash hands after using the toilet, changing nappies and before eating.
When cleaning vomit or diarrhoea, use disposable gloves if available, wash hands afterwards and clean the area thoroughly. Keep your child away from food preparation while they are ill and for 48 hours after symptoms stop.
What about babies?
Babies need extra caution. They can become dehydrated quickly and may not show symptoms as clearly as older children.
Continue breastfeeding or formula feeding. Offer smaller, more frequent feeds if needed. Do not dilute formula. Keep an eye on wet nappies, alertness, skin colour, breathing and whether your baby is feeding normally.
Seek medical advice if your baby is under 6 months and has vomiting or diarrhoea, has fewer wet nappies, is not feeding, has a fever, has green vomit, has blood in the stool, is unusually sleepy, or you are worried. Babies under 3 months with a temperature of 38°C or above should be assessed urgently.
Vomiting without diarrhoea: is it still a bug?
Sometimes vomiting starts before diarrhoea. But vomiting on its own can have other causes, including a urine infection, ear infection, migraine, food poisoning, appendicitis, bowel blockage, meningitis, raised pressure in the head, or a reaction to medicine.
Most single episodes of vomiting are not serious. But repeated vomiting, green vomit, severe headache, stiff neck, severe tummy pain, drowsiness, dehydration, vomiting after a head injury or vomiting in a very young baby should not be ignored.
Vomiting, diarrhoea and fever
A mild fever can happen with gastroenteritis. However, a persistent high temperature, a child who is becoming more unwell, or fever with rash, stiff neck, breathing difficulty, severe tummy pain or dehydration needs medical advice.
For detailed temperature advice, see our guide: Fever in Children: When to Worry and What to Do.
What not to do
Do not stop breastfeeding. Do not water down formula. Do not give fizzy drinks or fruit juice to treat dehydration. Do not give anti-diarrhoea medicine unless a doctor has advised it. Do not send your child back to nursery or school before 48 hours have passed since the last episode.
Do not worry if your child eats very little for a short period, but do take poor drinking seriously. Fluids matter most.
Do not wait too long if your child is becoming drowsy, has fewer wet nappies, cannot keep fluids down, has blood in the stool, has green vomit or has severe pain. These symptoms need medical advice.
A simple home monitoring plan
When your child has vomiting or diarrhoea, it helps to keep a rough note of what is happening. Write down when they vomit, how often they have diarrhoea, what fluids they are taking, when they last passed urine, and whether they have a fever or pain.
This does not need to be complicated. A few notes on your phone can be enough. If you later speak to NHS 111, a pharmacist or your GP, these details will help them judge the risk of dehydration and whether your child needs to be seen.
Look for the overall trend. A child who is drinking more, passing urine, vomiting less and becoming brighter is usually moving in the right direction. A child who is drinking less, passing less urine, becoming sleepier, developing pain or getting worse needs help.
Key takeaways
Vomiting and diarrhoea in children are usually caused by a stomach bug and often improve with home care. The most important treatment is regular fluids, given in small amounts if your child is vomiting. Oral rehydration solution can help replace lost salts and fluid when dehydration is a concern.
Seek urgent help if your child is very drowsy, floppy, confused, struggling to breathe, has green vomit, blood in the stool, severe constant tummy pain, signs of dehydration, a non-fading rash, or you think they are seriously unwell.
Keep children away from school or nursery until 48 hours after the last episode of vomiting or diarrhoea. This helps protect other children, staff and families.
Medical disclaimer: This guide is for general information only and does not replace medical advice. If you are worried about your child, contact your GP, pharmacist, NHS 111, or call 999 in an emergency.
FAQs about vomiting and diarrhoea in children
What is the most common cause of vomiting and diarrhoea in children?
The most common cause is viral gastroenteritis, often called a stomach bug. It usually improves on its own with fluids and rest.
How long does vomiting and diarrhoea last in children?
Vomiting often settles within 1 to 2 days. Diarrhoea can last several days and may take longer to fully return to normal. Seek advice if your child is getting worse, dehydrated, has blood in the stool, or symptoms are not improving.
What should I give my child to drink after vomiting?
Offer small, frequent sips of fluid. Water, breast milk, usual formula and oral rehydration solution are usually best. If your child vomits, pause briefly and restart with tiny amounts.
Should I stop milk if my child has diarrhoea?
Breastfed babies should continue breastfeeding. Formula-fed babies should usually continue their normal formula at normal strength. Do not dilute formula unless a healthcare professional tells you to.
Can children have oral rehydration solution?
Yes. Oral rehydration solution can be helpful if your child is at risk of dehydration or has mild dehydration. It is available from pharmacies. Follow the mixing instructions exactly.
Can I give my child anti-diarrhoea medicine?
Anti-diarrhoea medicines are generally not recommended for children unless a doctor specifically advises them. Ask a pharmacist, GP or NHS 111 before giving any medicine to stop diarrhoea.
When should I worry about dehydration?
Worry if your child is passing much less urine, has fewer wet nappies, has a dry mouth, no tears, sunken eyes, unusual drowsiness, cold hands and feet, or cannot keep fluids down. Seek medical advice urgently if these signs appear.
When should I call 999?
Call 999 if your child is very difficult to wake, floppy, confused, struggling to breathe, has blue lips, has a seizure, has green vomit, severe constant tummy pain, a stiff neck, or a rash that does not fade when pressed with a glass.
When should I call NHS 111?
Call NHS 111 if your child cannot keep fluids down, has signs of dehydration, has blood in the stool, has repeated vomiting, has diarrhoea many times in a day, is under 6 months and you are concerned, or you are unsure what to do.
Can my child go to school after vomiting once?
If your child has vomiting or diarrhoea from a suspected infection, they should stay off school or nursery until 48 hours after the last episode. This helps reduce spread.
Why does my child have a fever with vomiting and diarrhoea?
A fever can happen with gastroenteritis because the immune system is fighting infection. Seek advice if the fever is persistent, your child is very young, or there are worrying symptoms such as dehydration, rash, stiff neck, breathing difficulty or severe pain.
Is blood in diarrhoea serious?
Blood in the stool should be discussed with a healthcare professional. Seek urgent advice, especially if your child also has fever, severe tummy pain, dehydration or looks unwell.
What does green vomit mean?
Green vomit can be a warning sign of a blockage or other serious problem and needs urgent medical assessment.
Should I clean with hand gel or soap?
Use soap and water for handwashing, especially with stomach bugs such as norovirus. Alcohol hand gel is not as reliable for some causes of vomiting and diarrhoea.
What food is best after a tummy bug?
When your child is ready, offer small amounts of familiar foods such as toast, rice, pasta, potatoes, soup, yoghurt, crackers or bananas. There is usually no need for a very restricted diet.
