Baby Vomiting: Spit-up Isn't Vomiting — Knowing the ER Red Flags

"Spit-up" is not "vomiting" — and most baby vomiting isn't an emergency AAP definition: spit-up is the easy flow of stomach contents out (often with a burp); vomiting is forceful expulsion [1]Go to the ER now for: green/bilious vomit, projectile vomiting in a baby 2–8 weeks old, vomiting after a head injury, vomiting + stiff neck/severe headache

Baby vomiting is the worry that wakes parents up — but most of what new parents call "vomiting" in young infants is actually spit-up (gastroesophageal reflux): stomach contents flowing easily out of the mouth, often with a burp, not forceful expulsion [1].

The AAP draws the line precisely: "Vomiting is the forceful throwing up of stomach contents through the mouth. Spitting up (also known as gastroesophageal reflux, or GER) is the easy flow of stomach contents out of the mouth, frequently with a burp." [1]

This distinction matters — because spit-up is normal in babies under 12 months, while forceful, projectile vomiting in a 2–8-week-old can be a surgical emergency that needs to be fixed within days.

This guide pulls from AAP [1][2][3], NHS [4], CDC [5], and Bumrungrad Hospital [6] to help parents tell what's normal, what needs the doctor, and what's a 911-call right now.

🚨 Read this first — when vomiting means the ER

These signs are emergencies. Don't wait to "see how it goes":

NHS [4] and CDC [5] say clearly — call 1669 (Thai EMS) or go to the ER within the hour if any of:

• 🚨 Green or yellow-green vomit (bilious vomit) — possible bowel obstruction
• 🚨 Vomiting blood, or vomit that looks like coffee grounds — gastrointestinal bleeding
• 🚨 Projectile vomiting after every feed in a baby 2–8 weeks old — possible pyloric stenosis
• 🚨 Vomiting after a head injury or fall — especially more than once after the event
• 🚨 Vomiting + stiff neck + severe headache + light sensitivity — possible meningitis
• 🚨 Vomiting + severe abdominal pain with the baby crying inconsolably and arching the back
• 🚨 Babies under 3 months vomiting forcefully and refusing all feeds
• 🚨 Acute dehydration: sunken fontanelle, sunken eyes, no wet diaper for >8 hours, crying without tears, skin tenting, lethargy or hard to rouse

→ Call 1669 immediately or go to the ER. Do NOT give over-the-counter anti-emetic medicines.

Go to the doctor within 2–4 hours (urgent, not 1669-level)

AAP [1] lists these immediate red flags requiring doctor contact:

• Vomiting that continues beyond 24 hours
• Strenuous, repeated vomiting
• High fever > 38°C in an infant under 3 months, or > 39°C in older children
• Refusing all fluids — even breastmilk or ORS
• Swollen, tight abdomen, or rash, or jaundice

"Spit-up" vs "Vomiting" — how they differ

Spit-up is physiological gastroesophageal reflux — the lower esophageal sphincter is still developing. It happens in 40–50% of babies under 6 months [1]. If your baby still feeds well, plays normally, and gains weight, this isn't a disease and doesn't need medication.

The "happy spitter" who isn't happy — see your pediatrician (not an emergency, but don't wait it out) when spit-up comes with:

• No weight gain, or weight loss
• Crying as if in pain after every feed
• Spit-up tinged with blood, or green
• Persistent congested breathing or chronic cough from reflux into the airway

What actually causes vomiting in babies

1. Viral gastroenteritis ("stomach flu") — the #1 cause

NHS [4] confirms most pediatric vomiting is viral (rotavirus / norovirus) — "vomiting usually stops in 1 or 2 days".

Pattern:

• Vomiting first for 1–2 days, often followed by diarrhea for 5–7 days
• Low to moderate fever
• Other kids in the daycare/family sick at the same time

Care: see "How to handle ordinary vomiting" below — the focus is preventing dehydration. For the diarrhea side of the same illness see Baby diarrhea.

2. Pyloric stenosis — surgical emergency

AAP [2] calls it "the most frequent surgical condition in infants in the first few months of life". It's the most dangerous projectile-vomiting pattern in infants.

The classic 4-feature picture (all four = ER now):

1. Baby aged 2–8 weeks — "usually starting between 2 and 8 weeks of age" [2]
2. Projectile vomiting after every feed — "forcefully enough to launch their stomach contents several feet away" [2]
3. Hungry again right after vomiting — "hungry still (or again) after vomiting" [2] (the opposite of viral gastroenteritis, where the baby looks tired and uninterested in eating)
4. Boys are 4× more affected than girls [2]

The pediatrician will palpate for an olive-shaped mass in the upper belly and confirm with ultrasound.

Treatment: "The only dependable way to fix pyloric stenosis is to open the thickened pylorus muscle with surgery, a procedure called pyloromyotomy" [2]. Pyloromyotomy is safe and recovery is fast.

→ Don't wait — every day delayed means more dehydration and weight loss.

3. Intussusception — emergency

A baby 6 months – 2 years old with green/bilious vomit + paroxysmal abdominal pain + bloody "currant-jelly" stool → ER now. Treatment is air/contrast enema reduction or urgent surgery [1].

4. Cow's-milk allergy / FPIES

Baby under 6 months with repeated vomiting 2–4 hours after formula + lethargy + pallor → talk to your pediatrician about a hypoallergenic formula trial [1].

5. Head injury — emergency if vomiting recurs

CDC HEADS UP [5] is explicit — "Repeated nausea or vomiting" after a head bump is a danger sign requiring 911/ER.

If your baby falls off the bed or hits their head and then vomits:

• Vomits once + the baby is alert and acting normally → observe at home for 24 hours
• Vomits more than once, or becomes lethargic, hard to rouse, won't stop crying / can't be consoled, won't nurse or eat → ER now

CDC [5] adds for infants/toddlers: "Will not stop crying and cannot be consoled" and "Will not nurse or eat" = call 1669 / go to ER.

6. Other infections

Vomiting often comes alongside other infections (ear infection, pneumonia, urinary tract infection). Treat the underlying cause, not the vomiting.

How to handle ordinary vomiting (viral gastroenteritis)

1. Wait 30–60 minutes after a vomit before offering anything

Let the stomach rest — feeding too soon triggers another vomit.

2. Then offer fluids in tiny amounts every 5–10 minutes

NHS [4]: "carry on breast or bottle feeding your baby — if they're being sick, try giving small feeds more often than usual"

• Breastmilk: shorter, more frequent feeds (5–10 min every 30 min)
• Formula: start with about 1 oz every 30 minutes, slowly increase
• Babies > 6 months: offer oral rehydration salts (ORS) by teaspoon, every 5 minutes

If no vomit for 2–4 hours → gradually rebuild to normal volumes.

3. No solids in the first 24 hours

AAP [3]: "For the first 24 hours or so of any illness that causes vomiting, keep your child off solid foods".

After that, return to normal foods — there's no need for the old "rice/bananas only" rule (see Baby diarrhea — the BRAT diet is outdated).

4. Recheck for dehydration every 2–3 hours

Vomiting + diarrhea together causes dehydration fast. Watch for:

• Sunken fontanelle, sunken eyes
• Dry mouth and tongue, no saliva
• Crying without tears
• No wet diaper for >6–8 hours
• Skin tenting
• Lethargy, hard to rouse

→ ER now if 2 or more of these.

5. Should resolve in 1–2 days

NHS [4]: "vomiting usually stops in 1 or 2 days". If longer than that, see your doctor.

What NOT to do

❌ Don't give anti-emetic medicines on your own

AAP [3] is blunt: "you should never use over-the-counter or prescription remedies unless they've been specifically prescribed by your pediatrician for your child and for this particular illness".

Anti-emetics like domperidone or ondansetron should never be bought from the pharmacy and given to your baby on your own — in young children they can cause serious side effects (cardiac arrhythmias, extrapyramidal reactions). The pediatrician decides if and when these are needed.

❌ No fruit juice, fizzy drinks, or sports drinks

Wrong sugar-salt ratios make dehydration worse. Use ORS only.

❌ Don't force feed

When a baby keeps vomiting, the stomach needs rest. Wait 30 minutes after each vomit before trying again.

❌ No herbal remedies or "stomach tonics"

There's no evidence pharmacy "ya tat" digestive tonics or herbal teas stop vomiting in children, and some contain ingredients unsuitable for infants.

❌ No aspirin in a child with viral illness

Aspirin in a child with a viral infection can trigger Reye's syndrome — acute liver and brain damage. Use paracetamol/acetaminophen instead (ask your pharmacist).

Prevention — what helps before they get sick

Rotavirus vaccine — given from 2 months in Thailand

Rotavirus vaccine is in the Thai national EPI schedule and significantly reduces vomiting + diarrhea from rotavirus. See Baby diarrhea for the full schedule and age cut-offs.

Exclusive breastfeeding for the first 6 months

Reduces gastroenteritis and reduces spit-up frequency (less reflux than formula).

Feed positioning and burping

To reduce spit-up:

• Feed in a semi-upright position (not flat on back)
• Burp mid-feed and after every feed
• Hold upright for 20–30 minutes after feeds before laying baby down
• Don't overfeed — pace the feeds

Hand hygiene — especially against norovirus

• Wash hands before preparing milk/food and around diaper changes
• Wipe toys and surfaces with soap and water — alcohol gel doesn't kill norovirus well

How long it should take

NHS [4] says: ordinary vomiting resolves in 1–2 days. If it lasts longer, with dehydration setting in, see a doctor.

Cases that need the doctor even if the vomiting "doesn't look that bad":

• Babies < 3 months vomiting after every feed (concern for pyloric stenosis)
• Vomiting + diarrhea > 24 hours + dehydration signs
• Vomiting with any of the warning signs in the first section

Summary

When your baby vomits, start with the most important question: is this "spit-up" or actual "vomiting"?

Spit-up (easy flow with a burp; baby still happy, gaining weight) = normal in babies <12 months, no action needed.

Ordinary vomiting (viral gastroenteritis): wait 30–60 minutes after each vomit + tiny frequent fluid sips + monitor for dehydration + don't give OTC anti-emetics — usually resolves in 1–2 days.

Go to the ER now for any of:

• 🚨 Green/bilious vomit or vomit with blood / coffee-grounds
• 🚨 Projectile vomiting repeatedly in a 2–8-week-old + still hungry afterwards → possible pyloric stenosis
• 🚨 Vomiting after a head injury more than once, or with lethargy / inconsolable crying
• 🚨 Vomiting + stiff neck + severe headache + light sensitivity → possible meningitis
• 🚨 Dehydration: sunken fontanelle, sunken eyes, no wet diaper > 8 hours, skin tenting

Most baby vomiting isn't an emergency — but the 5 red flags above are the ones every parent should be able to recall.