The human mouth is basically a petri dish full of bacteria. Most experts think bad breath is caused by products of bacterial metabolism, like sulfur, volatile fatty acids, and other chemicals, like the appropriately named putrescine and cadaverine.

The prime source of these bacteria is the tongue, especially tongues that are heavily coated. These germs are also found between the teeth and gums (periodontal area).

What to do

Brushing or scraping the tongue, particularly the back half of the tongue, can help reduce bad breath in adults. While no studies on toddlers have been done, this is certainly a risk-free treatment you can try at home.

Mouthwashes, especially those that contain zinc, can also reduce bad breath in adults. But again, no studies have been done on toddlers, who may not be able to swish and spit a mouthwash.

Seeing a dentist, starting at age 1, for regular cleanings and checkups can help prevent poor dental health and tooth decay, which can contribute to bad breath.

Chronic sinusitis can be a possible cause of bad breath in toddlers. Children with this condition almost always have other signs or symptoms, such as:

  • prolonged runny nose
  • cough
  • nasal obstruction
  • facial pain

In addition, a foreign object stuck up the nose, such as a bead or piece of food, is common in this age group. This can also result in bad breath odor.

When this is the case, the child usually also has foul-smelling, and often green, discharge from the nose, often from just one nostril. In these instances, the odor may be remarkable and gets worse quickly.

What to do

If you think your child has sinusitis and it’s fairly recent in onset, then you can try to wait it out. Having your child drink lots of water and blowing their nose may help move things along faster.

But if you’ve tried these methods without benefit, then see your child’s doctor. Sometimes an antibiotic may be necessary to resolve chronic sinusitis.

If you think a foreign object is in your child’s nose, call your pediatrician. By the time it gets to the point of bad breath and green discharge, the object is now probably surrounded by swollen nasal tissue. It may be difficult to remove at home.

Your child’s doctor may be able to remove it in the office or refer you elsewhere.

Gastrointestinal (GI) causes of bad breath in toddlers aren’t as common as the other causes, but they need to be considered when other GI complaints are present.

If your child has chronic bad breath as well as abdominal pain, nausea, vomiting, or heartburn, then gastroesophageal reflux disease (GERD) is a possible culprit. In this condition, stomach acid will reflux (travel up) the esophagus, often into the throat or mouth, and in some cases, out the mouth.

Parents may be more familiar with GERD as an infant problem, but it can occur in the toddler years, too.

Infection with Helicobacter pylori, a type of bacteria that can infect the stomach and sometimes cause unpleasant symptoms, is another disease that can cause bad breath. Usually, this occurs in combination with other obvious GI complaints, like abdominal pain, nausea, vomiting, or burping.

H. pylori infection that causes symptoms is more common in older children and adults, but can occasionally be seen in toddlers as well.

What to do

These issues usually require treatment by a doctor. Medications are often prescribed for these condition, but your child may need further testing to determine if GERD or H. pylori is the cause of the problem.

If your child has frequent or chronic GI symptoms along with bad breath, talk to your pediatrician.

Children who breathe through their mouth while sleeping have a higher chance of having bad breath than children who don’t mouth breathe.

Mouth breathing can dry the oral mucosa, leading to a decrease in the flow of saliva. This results in a release of the foul-smelling bacteria in the mouth. Also, if your toddler drinks anything besides water from a bottle or sippy cup during the night, this may worsen the problem.

There are many reasons why children breathe only through the mouth, ranging from allergy-induced nasal congestion to large adenoids blocking their airway.

What to do

Brush your child’s teeth just before bed, then give them only water (or breast milk if they’re still breastfeeding at night) until morning.

If your child is persistently breathing through their mouth, ask your doctor for help. Because there are many causes of mouth breathing, some of which require medical attention, a doctor should examine your child to rule out any serious issues.

Just like adults, toddlers can have bad breath. There are a variety of different causes, from bacteria buildup in the mouth to stomach issues.

If you’re concerned about your child’s bad breath, their pediatrician can help you rule out the cause. Treating an underlying condition can help improve your toddler’s breath.