Vomiting in a newborn can be frightening. Many babies spit up — and most of the time it’s not dangerous. But in the first month of life, some types of vomiting need urgent medical assessment.

This guide will help you recognize:

  • What is likely normal spit-up
  • What is concerning vomiting
  • The most important red flags (especially green/bilious vomiting)
  • What you can do at home (when it is safe)
  • When to go to the emergency department

Important: In babies under 1 month, if you are unsure, it is safer to seek medical assessment.

Step 1: Red flags (go to Emergency now)

Seek urgent care now if your newborn has vomiting PLUS any of the following:

Vomit appearance

  • Green (bilious) vomiting → treat as an emergency until proven otherwise
  • Blood in vomit (bright red or coffee-ground material)
  • Vomiting that is forceful/projectile repeatedly (especially after feeds)

Baby’s condition

  • Very sleepy, hard to wake, unusually limp, or “not acting right”
  • Breathing difficulty, repeated choking, blue color, or pauses in breathing
  • Fever (rectal temperature 38.0°C or higher) in a baby < 3 months
  • Poor feeding or refusing feeds
  • Signs of dehydration:
    • Very dry mouth
    • No tears (older infants)
    • Fewer wet diapers (often < 4 wet diapers/day is concerning in young babies)
    • Sunken soft spot
    • Very sleepy or weak

Belly / stools

  • Swollen/firm belly
  • No stool or no passing gas with worsening vomiting
  • Blood in stool

If any red flag is present: do not wait at home.

Step 2: Spit-up vs vomiting (what’s the difference?)

“Spit-up” (reflux) — common and usually normal

  • Small to moderate amounts of milk coming up
  • Often occurs during burping or shortly after feeds
  • Baby otherwise looks well, feeds, and gains weight
  • No green color, no blood
  • Usually improves gradually over time

“Vomiting” — more concerning

  • Forceful or repeated emptying of stomach contents
  • May be associated with poor feeding, dehydration, lethargy, fever, or belly distension

Step 3: Common causes in newborns

1) Normal reflux / overfeeding

  • Most common
  • Triggered by large feeds, fast flow, swallowing air
  • Baby generally well

2) Viral illness or infection

  • In newborns, infections can be serious even with subtle symptoms
  • Vomiting with fever, lethargy, or poor feeding needs urgent evaluation

3) Milk protein allergy (less common in the first weeks but possible)

Clues:

  • Blood or mucus in stool
  • Eczema, irritability
  • Poor feeding, reflux-like symptoms This usually needs a clinician-guided plan.

4) Pyloric stenosis (typically starts around 2–8 weeks)

Clues:

  • Worsening projectile vomiting
  • Hungry after vomiting
  • Poor weight gain, dehydration This is urgent but usually not “green.”

5) Intestinal obstruction (emergency)

Clues:

  • Green (bilious) vomiting
  • Swollen belly, severe irritability, poor feeding Examples include malrotation/volvulus and other obstructive conditions.

Step 4: What you can safely do at home (only if no red flags)

If your baby is alert, feeding reasonably, has normal wet diapers, and vomit is NOT green or bloody:

Feeding adjustments

  • Offer smaller, more frequent feeds
  • Burp more often (mid-feed and after feed)
  • Keep baby upright for 20–30 minutes after feeds
  • If bottle-feeding: consider slower flow nipple if feeds are very fast

Monitor closely

  • Wet diapers, alertness, feeding volume
  • Any new fever, green vomit, or worsening pattern → seek care

Do not give anti-vomiting medications to a newborn unless instructed by a clinician.

Step 5: When to book a clinic visit (not emergency)

Book an appointment soon if:

  • Spit-up is frequent and baby seems uncomfortable most feeds
  • Poor weight gain
  • Suspected feeding difficulty (choking, coughing, very prolonged feeds)
  • Persistent vomiting but baby otherwise stable

Quick summary

  • Spit-up is common, but newborn vomiting requires caution.
  • Green (bilious) vomiting is an emergency.
  • Fever, lethargy, dehydration, blood, belly swelling, or projectile vomiting need urgent assessment.

If you want, the next post can be: Vomiting in toddlers: common causes, dehydration signs, and when to worry.