Baby Vomiting: Causes, Hydration & Red Flags | Parenting Hub
How to tell vomiting from reflux, keep babies hydrated through a tummy bug, and the warning signs that mean you need urgent medical care.
A vomit here and there is rarely cause for alarm — but watch for dehydration, projectile vomiting in young babies, and any green or bloody vomit.
Vomiting vs spit-up
Spit-up is the easy dribble of milk that comes with reflux. Vomiting is more forceful — the whole feed (or more) comes up, often with effort. Vomiting after most feeds, especially if it's projectile, always needs assessment.
Common causes
Most one-off vomits are nothing to worry about.
- Tummy bugs (viral gastroenteritis) — usually with diarrhoea
- Overfeeding or swallowed air
- A cold or cough triggering a cough-vomit
- Reflux that's worse than usual
- Less commonly: pyloric stenosis (in babies 2–8 weeks), urinary infection, or a blockage
What helps at home
The priority is keeping fluids in.
- Keep offering breast or formula in small, frequent amounts (every 15–20 minutes)
- For babies over 6 months on solids, oral rehydration solution between feeds can help
- Avoid fruit juice, soft drink or sports drinks — they make tummy bugs worse
- Watch nappies — at least 4–6 wet nappies in 24 hours is reassuring
When to see a doctor
See your GP if vomiting lasts more than 24 hours, your baby has fewer wet nappies, is unusually sleepy, or you're worried. Babies under 6 months get dehydrated faster — have a lower threshold for asking for help.
When to seek urgent care
Some symptoms need emergency assessment — don't wait it out.
When to seek help
- Green or yellow (bile-stained) vomit
- Blood in vomit
- Projectile vomiting after most feeds in a baby under 3 months
- Signs of dehydration: dry mouth, no tears, sunken fontanelle, very few wet nappies
- Drowsy, floppy, hard to rouse, or high-pitched cry
- Vomiting with a fever in a baby under 3 months
- Vomiting with a bulging soft spot, stiff neck or rash that doesn't fade under pressure
Common questions
How long does baby gastro usually last?
Vomiting from a tummy bug usually settles within 24–48 hours. Loose poos can hang around for a week or more. If vomiting goes beyond 24 hours or your baby looks unwell, see a GP.
Can I give my baby Hydralyte?
Oral rehydration solutions are safe from birth on a doctor's advice and from 6 months in small sips between feeds. Don't replace breast or formula feeds with it — offer it as well.