Projectile Vomiting in Babies

When to get help

Call emergency services or go straight to an emergency department — 999 in the UK, 112 or 999 in Ireland and across the EU, 911 in the US and Canada, 000 in Australia, 111 in New Zealand — if your baby's vomit is green or bright yellow, if it contains blood or looks like coffee grounds, if the tummy is swollen and hard, if your baby has severe tummy pain or draws the legs up screaming in bouts, if there is blood in the nappy, or if your baby is floppy, hard to wake or has a sunken soft spot. Green vomit means bile, and bile in a baby's vomit can mean a blockage in the bowel. It is assessed the same day, every time.

Seek urgent same-day advice — NHS 111 in the UK, your GP or out-of-hours service in Ireland, your paediatrician in the US or Canada, healthdirect on 1800 022 222 in Australia, Healthline on 0800 611 116 in New Zealand — if your baby is vomiting forcefully after most feeds, is not gaining weight or is losing it, has fewer wet nappies than usual, is under three months and has any fever, or seems constantly hungry despite bringing feeds back.

Posseting, reflux and projectile vomiting are three different things

Posseting is the small dribble of milk that appears on your shoulder after a feed. Reflux is milk coming back up the gullet, sometimes in larger volumes, in a baby who is otherwise well; the NHS notes that reflux is very common in the first months and usually improves as babies get older and start to sit up and take solids.

Projectile vomiting is different in force, not just volume. The milk leaves with real power, often landing a foot or more away, and it does not dribble. One projectile vomit means very little on its own — babies produce spectacular one-offs. The pattern that matters is projectile vomiting after most feeds, getting more frequent over days, in a baby of a particular age.

The pyloric stenosis pattern

Pyloric stenosis is a thickening of the muscle at the outlet of the stomach, which gradually blocks milk from passing into the intestine. Great Ormond Street Hospital describes the classic presentation: forceful vomiting shortly after feeds, usually starting in the first weeks of life, in a baby who then wants to feed again straight away.

Four features together make it likely enough to act on. First, the age: the American Academy of Pediatrics describes it as typically beginning between about two weeks and two months, and it is uncommon after around three months. Second, the force: vomiting that shoots rather than dribbles. Third, the hunger: unlike a baby with a stomach bug, a baby with pyloric stenosis is ravenous immediately afterwards, because nothing is getting through. Fourth, the trajectory: it gets worse over days rather than better, and weight gain stalls or reverses.

It is more common in first-born babies and in boys, and it runs in families, so mention it if a parent or sibling had it. The vomit is milk, not bile — it should not be green, because the blockage is above the point where bile enters.

What happens if pyloric stenosis is suspected

Expect a hands-on examination, sometimes during a feed, and an ultrasound scan of the tummy, which is how the diagnosis is usually confirmed. Blood tests check for the salt and fluid imbalance that repeated vomiting causes. If the scan confirms it, the treatment is an operation to divide the thickened muscle, usually done through keyhole surgery, but not until the fluid balance has been corrected first — that part is why babies are often on a drip for a day or so before theatre.

Recovery is generally quick and feeding restarts soon afterwards. It is one of the more reassuring diagnoses on this page precisely because it is fixable, provided it is picked up.

The other causes worth naming

Gastroenteritis causes vomiting that comes with diarrhoea, often a fever, and a baby who is off their feeds rather than desperate for them. A urine infection can present in a small baby as vomiting and being generally unwell with little else to see. Cows' milk protein allergy can cause frequent vomiting alongside eczema, blood or mucus in the stools, and distress. Overfeeding produces large, easy vomits in a thriving baby. And in a baby who is unwell with any infection, vomiting is a common non-specific sign.

Two patterns always outrank the rest: bile-stained vomiting, which suggests obstruction, and vomiting in a baby who is drawing their legs up in bouts and passing blood or mucus in the nappy, which can mean part of the bowel has telescoped into itself. Both are emergency-department problems.

Watching for dehydration

Whatever the cause, dehydration is the thing that turns a manageable problem into an urgent one, and in a small baby it moves in hours. Count wet nappies. Look for a dry mouth and tongue, no tears, unusual sleepiness or irritability, a sunken soft spot, and cold, blotchy hands and feet.

Keep offering breast or formula feeds, more often and in smaller amounts, rather than stopping milk. Do not dilute formula, and do not give plain water to a baby under six months as a rehydration measure. Ask before using an oral rehydration solution in a baby under one, because the advice depends on age and weight.

What to bring to the appointment

A short log is worth more than a long description: times of feeds, how much was taken, how soon afterwards the vomiting happened, the colour, and roughly how far it travelled. Add the number of wet nappies in the last 24 hours and your baby's recent weights from the red book or equivalent. A video of a typical vomit, if you happen to catch one, settles the projectile question in three seconds.