Causes of Infant Bad Breath and When to Worry

woman wiping baby’s mouth

When you think of bad breath, you generally don't think of a baby. After all, babies smell sweet unless they need their diaper changed, right? The fact is that while it is not all that common, infant bad breath may indicate something is wrong.

Health Issues That Cause Infant or Newborn Bad Breath

If your baby has bad breath, you'll need to search for the cause. The causes of a baby with bad breath are varied. Bad breath in infants and newborns should not be dismissed because it may signal an infection in the mouth or throat.


One possible reason for foul breath could be sinusitis. If your baby suffers from sinusitis, she will experience other symptoms like a nasal discharge and sneezing. While sinusitis symptoms mirror cold symptoms, sinusitis lasts longer than a cold. This condition can be the result of allergies, and it leads to stuffy sinus passages. As a result, the baby breathes solely through her mouth which dries saliva.

Less saliva than normal leads to a dry mouth, which may create bad breath. If you suspect a sinus infection, schedule an appointment with your health care provider to determine if your baby needs antibiotics.

Enlarged Tonsils

Other medical conditions that can lead to stinky breath are enlarged tonsils or adenoids. Healthy tonsils are generally pink and spot free, but infected ones are red, swollen, can have noticeable white spots, and smell terrible. Bacteria collects in the back of the throat and, paired with the sour smell of infection, this can cause stinky breath. If your child's tonsils look swollen or red, you should have your doctor examine her. Your pediatrician may prescribe an antibiotic to help take care of the infection.

Acid Reflux

Acid reflux can cause bad breath in infants. This condition is generally accompanied by the regurgitation of food. Acid reflux happens because the ring of muscle between the esophagus and the stomach is not yet fully mature and as a result, stomach contents flow backward resulting in your baby spitting up. This condition is rarely serious and should decrease as your baby gets older. Acid reflux usually does not continue after the age of age 18 months.

Reflux in babies usually clears up on by itself but there are a number of things you can do to help ameliorate the symptoms:

  • Give your baby smaller, but more frequent, feedings.
  • Burp your baby part way through her feeding.
  • Hold your baby upright for 20 to 30 minutes after feeding.
  • Try switching the type of formula you feed your baby.
  • Try using a different size nipple on your baby bottle. Nipples that are too large or small can cause your baby to swallow air.
  • If you're breast-feeding, try eliminating dairy products, beef or eggs from your diet, to test your baby for allergies.

Medications aren't normally recommended for infants with uncomplicated reflux. Your pediatrician may suggest trying an acid-blocking medication such as Zantac for babies 12 months or younger or Prilosec for toddlers age 1 year or older. Controlling your baby's acid reflux may eliminate her foul breath.

Less Serious Causes of Your Baby's Bad Breath

Bad breath in babies is not always the result of a health condition. The food or drinks you provide to your baby may stick to the tongue or around the gums and cause bacteria to grow, which in turn, causes the rotten smell. The growth of most odor-causing bacteria can be accelerated by less serious triggers like thumb sucking and using a pacifier, for example.

Thumb Sucking

Baby Girl

This is a common childhood activity that happens in about 80 percent of infants and children. Thumb sucking can lead to a dry mouth, increased bacteria and ultimately, bad breath. Most children will give up this habit between the ages of 2 and 4; only 12 percent of children will still be sucking their thumbs at age 4. Young children under the age of 4 don't require any treatment to stop the habit, and parents should wait to see if their child stops the behavior without intervention. To help alleviate infant bad breath that's caused by thumb sucking, use a warm, soft washcloth to clean your baby's mouth, gums and tongue regularly.

Pacifier Use

When your baby sucks on a pacifier, saliva and oral bacteria are transferred onto the pacifier. This may result in an unpleasant smelling pacifier which can then be transferred to your baby's mouth the next time she sucks on the pacifier. Also, if a pacifier is used multiple times without cleaning, this allows bacteria to multiply more quickly. To eliminate the stench of bad breath, you can stop using a pacifier altogether. If your baby isn't ready to give up his paci, take time to sterilize it often to kill the bacteria and germs present. Most children will stop using pacifiers between the ages of 2 and 4 years old. If your child is reluctant to give up the pacifier consider talking to your pediatrician or dentist for tips.

Sugar in Diet

When bottle-fed babies are put to bed with milk or formula, this can lead to the bacterial growth in the mouth and ultimately bad breath. To minimize bad breath and oral bacteria, practice good oral care with your baby.

  • Wipe down your baby's gums at least twice a day especially after feedings or before bed. Wiping her gums will wash off bacteria and prevent it from clinging to gums.
  • If your baby depends on a bottle to help him fall asleep, switch it out for a bottle of water which will not encourage the growth of bacteria that leads to bad breath.
  • If your baby is a little older, a diet that includes sugary drinks and other treats like pudding can help bacteria grow and cause bad breath.

Foreign Object

Occasionally babies lodge small foreign objects such as a pea or a piece of a toy in their nose without your knowledge. Not only does this cause poor breathing but it can also cause bad breath. If you believe that this is the reason for your child's bad breath, see your health care provider as soon as possible so she can check your child's nasal passages and remove the object.

When Infant Bad Breath May Indicate a More Serious Problem

Most of the time, bad breath in young children may be a sign of infection. You should speak with your pediatrician or dentist if your loved one has bad breath. In rare instances, bad breath can be a sign of a more serious condition.


Type one diabetes occurs when your child's pancreas stops producing insulin, a hormone that helps your body get energy from food. When this happens, the body's immune system attacks and destroys the cells that produce insulin in the pancreas (beta cells). There are a number of symptoms, that may be related to this condition, including foul breath.

Chronic Kidney Disease

This occurs when there is irreversible kidney damage or a reduction in kidney function. UptoDate, a clinical decision tool, notes that 20.1 percent of children under the age of 2 have this condition. Symptoms of chronic kidney disease can include:

  • Poor appetite
  • Vomiting
  • Headache
  • Stunted growth
  • General feeling of sickness
  • Chronic urinary tract infections
  • Urinary incontinence
  • Bad breath
  • Stomach mass

Optimal Oral Health for Your Baby

If your baby suffers from bad breath, it is best to bring the problem to your pediatrician's attention. The doctor will be able to diagnose sinusitis, infections or other health conditions that may be the culprit behind your baby's bad breath. Also, keep your baby's mouth clean and reduce the use of items that increase bacteria and cause bad breath. Providing your loved one with good oral care will help them maintain fresh breath.

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Causes of Infant Bad Breath and When to Worry