Stomach Bug in Kids: What to Give After Vomiting and When to Worry

Your child has thrown up three times in two hours, and now wants water. You hand over a glass, they drink the whole thing, and five minutes later it is all back up. The instinct is to give more. That is usually the thing that does not work.

• It typically runs three to seven days, with vomiting stopping before the diarrhoea
• The trick is not how much you give, but how little at a time
• Fizzy drinks and fruit juice can make diarrhoea worse
• Food comes back when your child asks for it, not on a schedule

Quick Reference

How long this actually takes

The NHS gives useful separate timelines, because the two symptoms do not end together: vomiting usually stops in 1 or 2 days, while diarrhoea usually stops within 5 to 7 days (NHS).

That gap is the part most parents are unprepared for. The day the vomiting stops feels like the end, and then the diarrhoea carries on for the rest of the week.

Symptoms vary a lot between children. Some only complain of stomach ache and go off their food, some vomit, some have diarrhoea, and some get all of it at once. Fever turns up sometimes, not always.

Most of it is viral. Rotavirus and norovirus are the usual culprits, and both are highly contagious.

Why a glass of water backfires

This is the part that changes the evening. When the stomach is irritated, a large volume arriving all at once tends to trigger another round, and your child ends up further behind than before.

So it goes the other way: small amounts, often. A tablespoon or two every 10 to 15 minutes does more than a glass every hour, because a glass gets tipped back and drained in one go. Treat that as a starting point rather than a dose: what is right for a six-year-old is not what is right for a baby, and how much your child manages to keep down matters more than the number. A spoon, a medicine syringe or a bottle cap all work better than a cup for exactly that reason.

What to offer:

• Oral rehydration solution from the pharmacy, particularly if the diarrhoea is heavy or there are early dehydration signs like dark or reduced urine.
• Water or squash, in small sips.
• Clear soup, which puts back some salt along with the fluid.

What to skip: fruit juice and fizzy drinks, which the NHS singles out because they can make diarrhoea worse.

Bringing food back

There is no need to starve a stomach bug out. Current NHS advice is to eat when you feel able to, avoiding food that is fatty or spicy.

In practice that means you do not push food while your child is actively vomiting, and you do not withhold it for days once their appetite starts returning. Plain, dull, low-fat things first: toast, rice, plain crackers, boiled potato, banana. If they want more, let them.

The older advice to keep children on a strictly restricted diet for days has fallen away. Getting normal food back in reasonably soon is now the mainstream position.

Signs of dehydration

This is the only part worth knowing by heart, because the rest can be looked up calmly.

• Fewer wet nappies, or noticeably less urine in an older child
• Dark, strong-smelling urine
• Dry mouth and tongue, crying without tears
• Pale skin, marked drowsiness, a child who is hard to rouse
• In babies: a sunken fontanelle

German paediatric guidance names a combination worth treating as an alarm: dry mouth, pale skin, sleepiness, and deep mouth-breathing. Small children dehydrate faster than adults, and in babies it can become dangerous within a short time.

For the detail on the youngest, baby dehydration: signs and what to do goes further, and hot weather speeds all of it up, which is covered in heat and dehydration in babies.

When to call

Straight away, without waiting, if there is blood in the vomit or stool.

Call 111 or your GP if a child under 5 shows signs of dehydration, such as fewer wet nappies, or if there is no improvement after about three days. A younger child has a lower threshold simply because the fluid loss moves faster.

If you are unsure whether what you are seeing is vomiting at all, vomiting vs spitting up draws the line, and for the fever side of it, when to monitor and when to call the doctor covers the thresholds.

Going back to nursery or school

Here two independent sources land on the same number, which is unusual enough to be worth trusting.

The NHS says to stay off school or work until you have not been sick or had diarrhoea for at least 2 days. German regulation is just as strict for children under six: return to a group setting is possible 48 hours after the symptoms have settled.

So 48 hours, not 24. And it counts from the last episode, not from when the illness started, which is the calculation most parents get wrong. Your setting may have its own written policy on top of that, so it is worth asking once.

If it feels like the group passes everything around, why kids get sick so often at daycare explains the arithmetic.

Stopping it going through the whole house

Handwashing is the main defence, and it is not the decorative kind. Everyone in the house, properly, before food and especially after the toilet.

Rotavirus and norovirus spread by contaminated surfaces, then hand to mouth. Pay particular attention to frequently touched surfaces such as door handles, taps and light switches, and to the toys that end up in mouths.

One hand towel per person, or paper towels while it lasts, does more than a deep clean.

Common mistakes

• Handing over a full glass. The fastest route to another round.
• Waiting until they ask for a drink. During vomiting you offer by the clock, not by thirst.
• Fizzy drinks to settle the stomach. They make the diarrhoea worse.
• Pushing food during the vomiting phase. It usually restarts it.
• Counting 48 hours from the start of the illness. It runs from the last episode.
• Asking for antibiotics. This is viral; they do nothing here.

If you do call, the numbers that help are the ones you are already counting: vomits and stools in the last 12 hours, wet nappies, what went in and stayed down. How to prepare for a pediatric visit using your child's data turns that into a two-minute handover.

Frequently asked questions

How long does a stomach bug last in children?

Vomiting usually stops within 1 to 2 days and diarrhoea within 5 to 7. The two do not end together, so the day the vomiting stops is rarely the end of it. If there is no improvement at all after about three days, contact your GP.

What should I give my child to drink after vomiting?

Small amounts often, roughly a tablespoon every 10 to 15 minutes rather than a glass at a time. Water, squash, clear soup and oral rehydration solution all work. Skip fruit juice and fizzy drinks, which can make the diarrhoea worse.

When can my child eat again?

When they feel able to, and not before. Avoid fatty and spicy food at first and start with plain things like toast, rice or banana. There is no need to keep a child on a restricted diet for days once their appetite comes back.

How do I tell a stomach bug from food poisoning?

Often you cannot, at least not in the first hours. Foodborne illness can start within hours, but depending on the organism it can also take a day or more, and it can come with a fever. The stronger clue is the pattern around you: suspect food when several people who ate the same meal fall ill in a similar window. The care is the same either way, so watching fluids and general condition beats guessing the cause.

When is vomiting an emergency?

If there is blood in the vomit or stool, if signs of dehydration appear such as a dry mouth, very little urine and marked drowsiness, or if there is severe stomach pain. In babies the threshold is lower because they lose fluid faster.

When can my child go back to nursery after a stomach bug?

After at least 48 hours with no vomiting and no diarrhoea, counted from the last episode rather than from the start of the illness. Both NHS and German guidance use the same 48-hour figure, and your setting may add its own rule.

How KidyGrow helps you

You do not need an app this week. You need a spoon, a rehydration sachet and patience.

What does get lost is when the last episode was, and that is the exact moment the 48 hours run from, and the exact thing nursery and your doctor will ask. You log a vomit or a bout of diarrhoea in two taps and the app remembers the time for you.

Day one that is just a list. After a few days the app learns the pattern, and your Daily Brief can read: "Last vomit yesterday at 2 PM, 19 hours clear since." That is a sentence you read out to the nursery instead of reconstructing two blurry days.

It helps when the same bug moves through the house too. You get the actual sequence: who started when, and how long it ran for each of them, so the conversation at the appointment does not begin with “everyone had something”.

Some weeks there is nothing to conclude, because teething, a cold and bad sleep all landed together. Then it says so instead of inventing a pattern.

There is one more thing afterwards. Appetite comes back slower than you expect, and a few days later you find yourself wondering whether that is the tail of the bug or something new. Having the last normal meal written down turns that into a question with an answer.

It will not wash the bedding. It will know that 31 hours have passed since the last episode, which is the one number you actually need right then.

Sources

1. NHS: Diarrhoea and vomiting (accessed 2026).
2. BIÖG, kindergesundheit-info.de: Durchfall bei Babys und Kleinkindern (accessed 2026).
3. BIÖG, kindergesundheit-info.de: Erbrechen bei Babys und Kleinkindern (accessed 2026).
4. RKI: Empfehlungen für die Wiederzulassung zu Gemeinschaftseinrichtungen gemäß § 34 IfSG (accessed 2026).

_Educational content. Not a substitute for medical advice._