🤢 Vomiting in Children (Newborns → Teens)

Common causes by age, dehydration signs, red flags, and what to do today

✅ Quick note: Vomiting is common in childhood. Most cases are caused by a short viral illness—but the risk changes by age. In newborns, vomiting can be serious even when symptoms look subtle. In toddlers, the biggest risk is dehydration. In older children and teens, causes broaden (migraine, constipation, appendicitis, reflux, stress). The key is spotting red flags early.

🧾 Quick “At-a-glance” box

✅ Condition/topic: Vomiting in children (age-specific guide)
Common parent terms: “Throwing up,” “spit-up,” “can’t keep anything down,” “green vomit,” “projectile vomiting”
What it is (2–3 lines): Vomiting is the forceful emptying of stomach contents. In many children it’s a short illness, but some vomiting patterns require urgent assessment—especially green (bilious) vomiting, vomiting with severe pain, dehydration, blood, or concerning behavior changes.
Who it affects (typical ages): All ages. Newborns (< 1 month) require extra caution.
✅ What parents should do today:
Check red flags first (especially green vomit and dehydration).
Use small, frequent fluids if no red flags.
Monitor urine output, energy, and pain pattern.
⚠️ Red flags that need urgent / ER care:
Green (bilious) vomit (bright green or green-yellow)
Blood in vomit or black “coffee-ground” vomit
Severe belly pain, worsening pain, hard/swollen belly, or pain localizing to the right lower belly
Very sleepy, confused, weak, “not acting right,” or hard to wake
Trouble breathing, repeated choking, blue color
Persistent vomiting with inability to keep down fluids
Severe headache, stiff neck, confusion, or vomiting after head injury
Severe testicular pain/swelling with nausea/vomiting (boys)
Suspected poisoning/medication ingestion (especially in toddlers/teens)
Newborn: fever (rectal 38.0°C or higher) or poor feeding
🟡 When to see the family doctor/clinic soon:
Vomiting lasting > 24–48 hours
Recurring episodes (weekly/monthly pattern)
Weight loss, poor growth, persistent belly pain
Morning vomiting or vomiting with headaches
Frequent constipation symptoms or reflux symptoms

🧠 What it is (plain language)

Vomiting can happen when:

The stomach or intestines are irritated (often a virus)
The brain’s vomiting center is triggered (migraine, head injury, severe pain)
The gut is blocked or twisted (rare, but urgent—especially if green vomit)
The body is fighting an infection (especially in newborns)

What part of the body is involved? (small diagram required)

Common myths vs facts

Myth: “If there’s no diarrhea, it’s not a virus.”
Fact: Viruses can cause vomiting without diarrhea—especially early.
Myth: “Green vomit is just bile and not serious.”
Fact: Green (bilious) vomiting can signal an intestinal blockage and needs urgent assessment.
Myth: “If my child wants water, give a big drink.”
Fact: Big drinks can trigger more vomiting. Small frequent sips work best.

🧩 Why it happens (causes & triggers)

Common causes (all ages, but vary by age)

Viral gastroenteritis (“stomach virus”)
Food-related triggers (overeating, food poisoning)
Constipation (yes, it can cause nausea/vomiting)
Reflux/gastritis (especially with burning upper belly pain)
Migraine or abdominal migraine (older kids/teens)
Stress/anxiety (older kids/teens)

Less common but important causes (brief)

Appendicitis
Urinary tract infection (especially toddlers)
Intestinal obstruction (especially urgent with green vomit)
Pyloric stenosis (usually 2–8 weeks, projectile vomiting)
Head injury or neurologic illness
Poisoning/ingestions

👀 What parents might notice (symptoms)

Typical symptoms

Nausea, vomiting episodes
Tummy cramps
Fever (sometimes)
Diarrhea (sometimes)
Reduced appetite and tiredness

Symptoms by age group (high-yield)

Newborns (0–28 days): feeding changes, sleepiness, fewer wet diapers, fever—may be subtle but serious
Toddlers (1–4 years): dehydration risk rises quickly; may vomit from cough/mucus, ear infection, or UTI
Older children/teens: migraine patterns, stress patterns, appendicitis clues, constipation/reflux

What’s normal vs what’s not normal

✅ Often reassuring: brief vomiting with stable hydration, improving energy, no severe pain, no green/bloody vomit
⚠️ Not reassuring: green vomit, blood, severe localized pain, dehydration, neurologic symptoms, newborn vomiting with fever/poor feeding

Symptom tracker (what to write down)

Time and number of vomits
Color (clear, yellow, green, bloody, coffee-ground)
Urine output (how often peeing/wet diapers)
Fever (and temperature)
Belly pain location and severity
Diarrhea or constipation symptoms
Headache, neck stiffness, behavior changes
Any possible ingestion (meds, alcohol, toxins)

🏠 Home care and what helps (step-by-step)

✅ Do this now (if no red flags): Prevent dehydration with small, frequent fluids.

What to do in the first 24 hours

Rest the stomach, not the child: let them rest, but keep fluids going
Offer oral rehydration solution (best), especially if there is diarrhea
Use a sip schedule:
- Give a few sips every 1–2 minutes
- If they vomit, wait 5–10 minutes, then restart slower
Avoid fatty, heavy foods during active vomiting
Once fluids stay down, offer simple foods as tolerated (toast, rice, soup, yogurt)

What fluids are best?

✅ Oral rehydration solution is best
✅ Water is okay temporarily if no ORS available
🟡 Avoid large amounts of juice/pop (can worsen diarrhea)

What usually makes it worse

Big gulps of water
Forcing food during active vomiting
Greasy foods
Treating dehydration late

⛔ What NOT to do (common mistakes)

Do not ignore green vomit.
Do not give anti-vomiting medications to newborns unless instructed by a clinician.
Do not give large drinks “to catch up.”
Do not assume vomiting is “just stress” if there is weight loss, morning vomiting, or headaches.

🚦 When to worry: triage guidance

🔴 Call 911 / Emergency now

Trouble breathing, blue color, repeated choking
Collapse, severe weakness, very hard to wake
Severe head injury symptoms with repeated vomiting and confusion

Example: “My child is vomiting and is very hard to wake or acting confused.”

🟠 Same-day urgent visit (ER / urgent care)

Green (bilious) vomit
Blood in vomit or black “coffee-ground” vomit
Persistent vomiting with inability to keep down fluids
Severe belly pain, hard/swollen belly
Pain localizing to the right lower abdomen (appendicitis concern)
Severe testicular pain/swelling with vomiting (boys)
Severe headache, stiff neck, confusion
Suspected poisoning/ingestion
Newborn: fever (rectal 38.0°C or higher), poor feeding, lethargy, fewer wet diapers

Example: “The vomit is green and they can’t keep fluids down.”

🟡 Book a routine appointment

Vomiting lasts > 24–48 hours
Recurring episodes (weekly/monthly pattern)
Weight loss, poor growth, chronic belly pain
Morning vomiting, or vomiting with headaches
Ongoing reflux/gastritis symptoms
Constipation symptoms that keep returning

Example: “They vomit every few weeks with headaches and light sensitivity.”

🟢 Watch at home

Mild vomiting that is improving
Child can keep down small frequent fluids
Urine output is okay and energy is returning
No red flags

Example: “They vomited twice, now sipping fluids and peeing normally.”

🩺 How doctors diagnose it (what to expect)

What the clinician will ask

Vomit color (green? blood?)
Number of episodes and ability to keep fluids down
Urine output and dehydration signs
Belly pain location (especially right lower abdomen)
Fever and sick contacts
Headache/neck stiffness/head injury
Stool pattern (diarrhea vs constipation)
Medications and possible ingestions
In newborns: feeding pattern and wet diapers

Physical exam basics

Hydration and vital signs
Belly exam (tenderness, guarding, distension)
Throat/ears/lungs as needed
Neuro exam if headache/head injury concerns
Testicular exam if indicated (boys with lower belly pain + vomiting)

Possible tests (and why)

Urine test (especially toddlers with fever/vomiting)
Blood tests if dehydration is significant or diagnosis unclear
Imaging if appendicitis or obstruction concern
In newborns: infection evaluation if fever or concerning behavior

What tests are usually not needed

Extensive testing in a typical short viral illness with improving symptoms and no red flags

What results might mean (simple interpretation)

Viral illness: supportive care + hydration
Appendicitis/obstruction concerns: urgent surgical evaluation
Migraine patterns: targeted migraine plan
Constipation/reflux: treat underlying driver to stop recurrence

🧰 Treatment options

First-line treatment (most cases)

Oral rehydration solution + small frequent sips
Rest, simple foods when ready
Treat constipation if suspected
Avoid stomach irritants (for example frequent ibuprofen on an empty stomach)

If not improving (next steps)

Clinic reassessment for dehydration, pain pattern, and red flags
Consider targeted evaluation for migraine, reflux/gastritis, constipation, appendicitis, urinary infection
Consider referral if recurrent vomiting episodes persist

Severe cases (hospital care)

Significant dehydration
Inability to keep fluids down
Concern for appendicitis, obstruction, or serious infection (especially newborns)

⏳ Expected course & prognosis

Typical timeline

Viral vomiting often improves within 24–72 hours
Appetite may take a few days to return
Dehydration improves quickly once fluids are tolerated

What “getting better” looks like

Longer gaps between vomiting
Able to keep down small frequent fluids
Urine output improves
Energy starts returning

What “getting worse” looks like

Vomiting becoming more frequent
New severe belly pain or localized right lower pain
Vomit turns green or bloody
Urine output drops, child becomes very sleepy

Return to school/daycare/sports guidance

Return when vomiting has stopped, hydration is good, and energy is adequate
Send water and simple snacks initially

⚠️ Complications (brief but clear)

Common complications

Dehydration
Temporary weight loss
Constipation after an illness (reduced intake can trigger it)

Rare serious complications (red-flag reminder)

Appendicitis
Intestinal obstruction (especially with green vomit)
Serious infection in newborns
Head injury complications

🛡️ Prevention and reducing future episodes

Hand hygiene (reduces viral spread)
Hydration during illnesses
Avoid constipation cycles (fiber, fluids, routine)
Identify and treat migraine triggers in recurrent patterns
For reflux/gastritis: avoid frequent stomach irritants and discuss persistent symptoms with a clinician

🌟 Special situations (by age)

👶 Newborns (0–28 days): extra caution

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

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

Spit-up (reflux) — common and usually normal

Small/moderate milk coming up during burping or after feeds
Baby otherwise looks well, feeds, gains weight
No green color, no blood

Vomiting — more concerning

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

Newborn red flags (ER now)

Green (bilious) vomiting
Blood in vomit
Repeated forceful/projectile vomiting (especially worsening)
Fever (rectal 38.0°C or higher)
Very sleepy, limp, “not acting right”
Poor feeding or fewer wet diapers
Swollen/firm belly, no stool/gas with worsening vomiting
Breathing difficulty, repeated choking, blue color

Common causes in newborns

Normal reflux/overfeeding
Infection (can be subtle—needs urgent evaluation if fever/lethargy/poor feeding)
Milk protein allergy (possible)
Pyloric stenosis (often 2–8 weeks; projectile vomiting; hungry after vomiting)
Intestinal obstruction (emergency—often with green vomit)

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

Smaller, more frequent feeds
Burp more often
Keep upright 20–30 minutes after feeds
Monitor wet diapers and alertness
No anti-vomiting medicines unless clinician instructed

👧🧒 Toddlers (1–4 years): dehydration-focused

Most common causes

Viral gastroenteritis
Food-related causes (overeating, food poisoning)
Constipation
Ear infection/respiratory illness (vomiting from coughing/mucus/fever)
Urinary tract infection (can present as fever + vomiting)

How to tell if dehydration is starting

Dry mouth, cracked lips
Fewer wet diapers/less peeing
No tears when crying
Sunken eyes
Unusual sleepiness or irritability
Fast breathing or fast heart rate

🧑‍🎓 Older children and teens: broader causes

Common causes in older kids/teens

Viral gastroenteritis
Appendicitis (important not to miss)
Migraine / abdominal migraine
Constipation
Reflux / gastritis
Anxiety/stress patterns

Appendicitis clues (seek urgent assessment)

Pain starts around belly button then moves to right lower belly
Pain worsens with movement/jumping
Reduced appetite, fever, vomiting

Migraine / abdominal migraine clues

Episodes of vomiting with headache
Sensitivity to light/sound
Family history of migraine
Belly pain can be the main symptom in some children

📅 Follow-up plan

Follow up with your clinician if:
- vomiting lasts > 24–48 hours
- hydration is borderline
- belly pain persists or localizes
- vomiting recurs in episodes (weekly/monthly pattern)
Bring:
- timeline of vomiting episodes
- urine output estimate
- fever measurements
- pain location pattern
- headache history, constipation symptoms, and triggers

❓ Parent FAQs

“Is it contagious?”

Often yes when it’s viral. Hand hygiene and cleaning shared surfaces help.

“Can my child eat ___?”

During active vomiting, focus on fluids. Once fluids stay down, offer simple foods as tolerated. Avoid forcing food.

“Can they bathe/swim/exercise?”

Yes if hydrated and energy is normal. Avoid intense activity during active vomiting or dehydration.

“Will they outgrow it?”

Most viral vomiting episodes resolve. Recurrent patterns (migraine, reflux, constipation) improve with targeted management.

“When can we stop treatment?”

When your child is drinking normally, peeing normally, and vomiting has stopped. Continue monitoring for 24 hours.

🧾 Printable tools

🧾 Printable: One-Page Action Plan (Vomiting)

Step 1: Check red flags

Green (bilious) vomit
Blood/coffee-ground vomit
Severe belly pain / swollen hard belly
Right lower belly pain (appendicitis concern)
Very sleepy/confused/hard to wake
Trouble breathing/blue color
Cannot keep down fluids
Severe headache/stiff neck/head injury vomiting
Severe testicular pain/swelling (boys)
Suspected poisoning/ingestion
Newborn fever (rectal 38.0°C or higher) or poor feeding

➡️ If any checked: urgent care now.

Step 2: If no red flags

Oral rehydration solution (preferred)
Small sips every 1–2 minutes
If vomit occurs: wait 5–10 minutes, restart slower
Monitor urine output and energy

🧾 Printable: Medication Schedule Box

Use only if your child has clinician-prescribed medications.

Morning: ____________________ Time: ______
Afternoon: __________________ Time: ______
Evening: ____________________ Time: ______
Notes / side effects to watch: ______________________________________

🧾 Printable: Dehydration Tracker

Date: _______

Wet diapers/peeing: normal / less / very low
Mouth: moist / dry
Tears when crying: yes / no
Energy: normal / tired / very sleepy
Fluids kept down: yes / no
Vomiting count today: ____
Notes: _______________________________________________

🧾 Printable: “Red flags” fridge sheet

⚠️ Urgent care if: green vomit, blood/coffee-ground vomit, severe belly pain or swollen hard belly, right lower belly pain, dehydration with low urine, very sleepy/confused, trouble breathing/blue color, cannot keep fluids down, severe headache/stiff neck/head injury vomiting, testicular pain/swelling, suspected poisoning, or newborn fever/poor feeding.

🧾 Printable: School/Daycare Instructions Page

Vomiting illness support plan

Encourage frequent small sips of fluid
Allow bathroom access and rest breaks
Notify parent if vomiting recurs, child becomes very sleepy, or belly pain becomes severe
Child should go home if unable to keep fluids down or appears dehydrated

📚 Credible sources + last updated date

Trusted references (examples):

American Academy of Pediatrics (HealthyChildren.org): vomiting, dehydration, and gastroenteritis guidance
Children’s hospital resources on oral rehydration and dehydration warning signs
Pediatric surgery/children’s hospital pages on appendicitis warning signs
Pediatric migraine education resources (children’s hospitals)
Poison control resources for ingestion emergencies

Last reviewed/updated on: 2025-12-27
Local guidance may differ based on your region and your child’s health history.

🧡 Safety disclaimer

This guide supports—not replaces—medical advice. If you are worried about your child, trust your instincts and seek urgent medical assessment.

This guide was fully developed & reviewed by Dr. Mohammad Hussein, MD, FRCPC ROYAL COLLEGE–CERTIFIED PEDIATRICIAN & PEDIATRIC GASTROENTEROLOGIST
Board-certified pediatrician and pediatric gastroenterologist (Royal College of Physicians and Surgeons of Canada) with expertise in inflammatory bowel disease, eosinophilic gastrointestinal disorders, motility and functional testing, and complex nutrition across diverse international practice settings.
To book an online assessment Email Dr. Hussein’s Assistant Elizabeth Gray at: Elizabeth.Gray@pedsgimind.ca
In the email subject, please write: New Assessment Appointment with Dr. Hussein
Important: This appointment is completely online as Dr. Hussein is currently working overseas.
This service is not covered by OHIP