Infant Vomiting: Causes, Treatment & When to Worry

What Causes Vomiting in Infants Under One Year?

The most common causes of infant vomiting are gastroesophageal reflux (spitting up), viral gastroenteritis, overfeeding, and respiratory infections. Less common but important causes include pyloric stenosis, food allergies, and intestinal obstruction.

Babies vomit for many reasons, and the cause often determines whether you need to worry. Understanding these causes helps you respond appropriately and know when professional evaluation is needed.

Gastroesophageal Reflux (Spitting Up)

The most common reason babies appear to vomit is actually gastroesophageal reflux, commonly called spitting up. This happens because the muscle between the esophagus and stomach isn't fully developed in infants. After feeding, some milk flows back up and out of the mouth.

Spitting up is considered normal when babies are otherwise happy, growing well, and not distressed. It typically peaks around 4 months of age and resolves by 12-18 months as the digestive system matures. This is sometimes called "happy spitter" syndrome.

However, when reflux causes distress, poor weight gain, or other complications, it may be gastroesophageal reflux disease (GERD), which requires medical evaluation and treatment.

Gastroenteritis (Stomach Flu)

Viral gastroenteritis is another very common cause of vomiting in infants. Unlike reflux, gastroenteritis causes forceful vomiting that often comes on suddenly. Babies may vomit even after taking small amounts of fluid. The vomiting usually lasts 1-3 days and may be followed by diarrhea.

Rotavirus and norovirus are the most common culprits. Gastroenteritis spreads easily in families and childcare settings. The main concern is dehydration, so maintaining fluid intake is crucial.

Overfeeding

Babies, especially newborns, can easily take in more milk than their small stomachs can hold. This "overflow" vomiting happens right after feeding and brings up undigested milk. It's more common with bottle-feeding, where controlling flow is harder than with breastfeeding.

Signs of overfeeding include vomiting after every feed, excessive spit-up, and a distended belly after feeding. Smaller, more frequent feedings usually solve this problem.

Respiratory Infections

Babies with colds, bronchiolitis, or other respiratory infections often vomit. Swallowed mucus irritates the stomach, and coughing fits can trigger vomiting. Fever itself can also cause nausea and vomiting in infants.

With respiratory infections, the vomiting usually improves as the infection clears. Watch for signs that the respiratory infection is severe, such as difficulty breathing, rapid breathing, or blue coloring around the lips.

Food Allergies and Intolerances

Cow's milk protein allergy affects about 2-3% of infants and can cause vomiting, especially when formula-fed babies first start formula or when new foods are introduced. Symptoms may appear immediately after feeding or several hours later.

Other common food allergens that may cause vomiting in older infants (when solid foods begin) include eggs, soy, wheat, and fish. If you suspect a food allergy, consult your pediatrician before eliminating foods from your baby's diet.

Pyloric Stenosis

Pyloric stenosis is an important condition to recognize. It occurs when the muscle at the stomach outlet becomes abnormally thick, preventing milk from passing into the small intestine. It typically develops between 2 and 8 weeks of age.

The classic symptom is projectile vomiting - forceful vomiting that can travel several feet. Babies with pyloric stenosis are hungry immediately after vomiting and want to feed again. They may become dehydrated and lose weight. Pyloric stenosis is more common in firstborn males and requires surgical correction.

When Should I Worry About My Baby's Vomiting?

Seek immediate medical care if your baby's vomit contains blood or bile (green/yellow), if your baby shows signs of dehydration, has a bulging or sunken fontanelle, is unusually sleepy or difficult to wake, or has projectile vomiting starting between 2-8 weeks of age.

Most infant vomiting doesn't require emergency care, but certain signs indicate potentially serious conditions that need prompt evaluation:

Concerning Vomiting Patterns

• Projectile vomiting in young infants (2-8 weeks): May indicate pyloric stenosis
• Vomiting with every feed: Could suggest obstruction or severe reflux
• Vomiting that worsens over days: Needs evaluation for underlying cause
• Vomiting after head injury: May indicate concussion

Associated Symptoms Requiring Medical Attention

• Fever over 38C (100.4F) in babies under 3 months
• Refusing to feed or unable to keep any fluids down
• Diarrhea lasting more than 24 hours
• Signs of abdominal pain (drawing legs up, excessive crying)
• Poor weight gain or weight loss
• Rash, especially if it doesn't fade when pressed

How Can I Tell if My Baby is Dehydrated?

Early signs of dehydration include fewer wet diapers (less than 6 in 24 hours), dark urine, dry lips and mouth, and increased thirst. Severe dehydration causes sunken fontanelle, sunken eyes, no tears when crying, cool mottled skin, and extreme sleepiness.

Dehydration is the main risk of vomiting in infants. Babies become dehydrated faster than older children because of their small body size and higher metabolic rate. Recognizing dehydration early allows you to intervene before it becomes serious.

Mild Dehydration Signs

• Slightly fewer wet diapers than usual
• Slightly darker urine
• Dry lips
• More interested in feeding than usual

Mild dehydration can usually be managed at home with frequent small fluid offerings.

Moderate Dehydration Signs

• Noticeably fewer wet diapers (less than 4 in 24 hours)
• Dark yellow or amber urine
• Dry mouth and tongue
• Fewer tears when crying
• Slightly sunken eyes
• Mild irritability or fussiness

Moderate dehydration needs medical evaluation. Call your doctor or health advice line.

Severe Dehydration Signs (Emergency)

• No wet diaper for 6 or more hours
• Sunken soft spot (fontanelle) on top of head
• Very sunken eyes
• No tears when crying
• Very dry mouth and lips
• Cool, mottled hands and feet
• Extreme sleepiness or difficulty waking
• Rapid breathing or heartbeat

Severe dehydration is a medical emergency. Seek immediate care.

How Do I Treat Vomiting at Home?

For mild vomiting, wait 30-60 minutes after an episode, then offer small amounts of breast milk, formula, or oral rehydration solution frequently. Keep your baby upright after feeding, burp gently, and monitor for dehydration. Continue breastfeeding if your baby tolerates it.

Most vomiting episodes in healthy infants can be managed at home with simple measures focused on preventing dehydration and keeping your baby comfortable.

Immediate Care After Vomiting

1. Wait before feeding: After vomiting, wait 30-60 minutes before offering any fluids. This gives the stomach time to settle.
2. Start with small amounts: Begin with 1-2 teaspoons (5-10 ml) of breast milk, formula, or oral rehydration solution every 5-10 minutes.
3. Increase gradually: If your baby keeps the small amounts down for 30-60 minutes, slowly increase the volume.
4. Return to normal feeding: Once vomiting stops for several hours, gradually return to normal feeding patterns over 24-48 hours.

For Breastfed Babies

Continue breastfeeding, but offer shorter, more frequent feeds rather than longer sessions. Breast milk is easily digested and provides hydration, nutrition, and infection-fighting antibodies. If your baby has gastroenteritis, your breast milk may contain specific antibodies against the virus.

For Formula-Fed Babies

Offer smaller amounts of formula more frequently. If vomiting persists, your doctor may recommend switching to a lactose-free or hydrolyzed formula temporarily. Don't dilute formula - this changes its nutritional balance and can be harmful.

Oral Rehydration Solutions

Commercial oral rehydration solutions (ORS) are specially formulated to replace fluids and electrolytes lost through vomiting and diarrhea. They're more effective than water, juice, or sports drinks for rehydration.

Offer ORS in small, frequent amounts - 1-2 teaspoons every few minutes. For babies over 6 months, ORS can be frozen into popsicles for easier administration.

Positioning and Comfort

• Keep your baby upright for 20-30 minutes after feeding
• Burp gently and thoroughly during and after feeds
• Avoid jostling or active play right after feeding
• Keep your baby's head elevated slightly when lying down (but never use pillows or positioners in the crib)
• Dress your baby in easily changeable clothes

How Can I Prevent My Baby From Vomiting?

While you can't prevent all vomiting, you can reduce its frequency by feeding smaller amounts more often, burping regularly, keeping baby upright after feeds, and practicing good hygiene to prevent infections. For reflux, try paced bottle feeding and check bottle nipple flow.

Feeding Techniques to Reduce Vomiting

• Smaller, more frequent feeds: Offer less milk more often rather than large feeds
• Burp frequently: Burp after every 1-2 ounces for bottle-fed babies, or when switching breasts
• Pace bottle feeding: Hold the bottle more horizontally and allow breaks during feeding
• Check nipple flow: A nipple flow that's too fast can cause gulping and overfeeding
• Keep baby calm during feeds: Feed in a quiet environment when baby is calm, not frantically hungry
• Upright positioning: Keep baby semi-upright during and after feeds

Preventing Gastroenteritis

• Wash hands frequently, especially after diaper changes and before feeding
• Keep your baby up to date on rotavirus vaccination
• Avoid contact with people who have stomach bugs
• Clean and sterilize bottles and feeding equipment properly
• Practice safe food handling when preparing formula or solid foods

When Starting Solid Foods

• Introduce new foods one at a time, waiting 3-5 days between new foods
• Start with small amounts
• Watch for allergic reactions including vomiting
• Ensure food is properly prepared and age-appropriate in texture

What Medical Treatments Are Available?

Medical treatment depends on the cause. Gastroenteritis usually requires only supportive care and rehydration. Pyloric stenosis needs surgery. GERD may be treated with thickened feeds, positioning changes, or medication. Severe dehydration requires IV fluids.

When home care isn't enough or the underlying cause requires specific treatment, doctors have several options:

For Dehydration

If your baby can't keep fluids down or shows signs of moderate to severe dehydration, they may need IV (intravenous) fluids. This quickly restores hydration and electrolyte balance. Most babies improve rapidly with IV rehydration.

For Gastroesophageal Reflux Disease (GERD)

Simple reflux doesn't usually need treatment, but GERD may be managed with:

• Thickened feeds: Adding rice cereal to formula (only on medical advice)
• Positioning therapy: Keeping baby upright after feeds
• Medications: Acid-reducing medications may be prescribed for severe cases
• Hypoallergenic formula: If milk allergy is suspected

For Pyloric Stenosis

Pyloric stenosis requires a surgical procedure called pyloromyotomy. The surgeon cuts through the thickened muscle to open the passage from stomach to intestine. This is a common, safe procedure with excellent outcomes. Most babies can feed normally within hours of surgery and go home within 1-2 days.

For Food Allergies

If a food allergy is diagnosed, the treatment is eliminating the allergen from the diet. For cow's milk protein allergy in formula-fed babies, this means switching to a hydrolyzed or amino acid-based formula. For breastfed babies, the mother may need to eliminate dairy from her diet.

For Intestinal Obstruction

Intestinal obstruction (including intussusception and volvulus) is a medical emergency requiring immediate hospital treatment. Depending on the type and severity, treatment may involve:

• Air or contrast enema to reduce intussusception
• Surgery to correct the obstruction
• IV fluids and nasogastric tube to decompress the stomach

Does Vomiting Differ at Different Ages?

Yes, the causes and concerns vary by age. Newborns (0-4 weeks) with vomiting need careful evaluation. Babies 2-8 weeks old with projectile vomiting may have pyloric stenosis. Older infants (6-12 months) may vomit from gastroenteritis or when introducing new foods.

Newborns (0-4 Weeks)

Vomiting in the first few weeks of life deserves careful attention because:

• Serious conditions like intestinal malformations may first appear as vomiting
• Newborns dehydrate quickly
• Infections in newborns can be more serious
• Breastfeeding is being established, so technique issues are common

Contact your doctor if a newborn vomits repeatedly, has bile-stained vomit, or isn't gaining weight appropriately.

1-4 Months

This is the peak age for reflux and spitting up. It's also when pyloric stenosis typically appears (usually 2-8 weeks). Watch for:

• Projectile vomiting that seems to be getting worse
• Baby who is hungry immediately after vomiting
• Poor weight gain despite good appetite

4-6 Months

Spitting up usually starts to improve around this age. Babies are more alert and active, which can affect feeding and digestion. Gastroenteritis becomes more common as babies put more objects in their mouths and may be in group childcare.

6-12 Months

As solid foods are introduced, vomiting may occur with:

• New food allergies or intolerances
• Texture issues as baby learns to manage solid foods
• Choking or gagging on lumpy foods (though this isn't true vomiting)
• Continued gastroenteritis exposure

Reflux typically resolves by 12 months in most babies.

What About Special Situations?

Vomiting After Vaccinations

Some babies vomit after vaccinations as part of a mild reaction. This is usually not concerning if it's a single episode without other worrying symptoms. However, if your baby received the rotavirus vaccine and vomits repeatedly or has severe abdominal pain, contact your doctor as rarely intussusception can occur.

Vomiting During Travel

Motion sickness is rare in babies under 2 years old but can occur. Car seat positioning that allows the baby to look out the window may help. Avoid feeding immediately before travel. If motion sickness is a problem, speak to your doctor about strategies.

Vomiting with Chronic Conditions

Babies with certain chronic conditions may be at higher risk from vomiting:

• Premature babies may have more reflux and feeding difficulties
• Babies with heart conditions may dehydrate more easily
• Babies on medications may vomit them up, affecting treatment

If your baby has a chronic condition and is vomiting, follow your healthcare team's specific guidance.

Suspected Poisoning

If you think your baby has swallowed something toxic - medication, household chemicals, plants - call your local poison control center immediately. Do NOT induce vomiting unless specifically instructed to do so, as some substances cause more damage coming back up.