Why a child’s mouth can be unpleasant, whether parents should be worried, how to get rid of the smell, and when to go to the dentist.

What is halitosis?

Halitosis is a condition in which an unpleasant odor appears from the mouth. It can arise for various reasons, be temporary or chronic.

What causes bad breath in children?

Poor oral hygiene

The most common cause of bad breath in children is insufficient oral hygiene.
If plaque (the sticky bacterial film that forms on the teeth) and food debris are not removed by proper brushing, the bacteria in the mouth have something to feed on. When they eat, they emit smelly volatile sulfur compounds, so the smell from the child’s mouth becomes sour and unpleasant.


Eating certain foods can cause bad breath. Digestion begins with the first bite of food, and everything your baby eats crumbles in his mouth, which can cause bad breath.

Foods that contain sulfur, such as garlic and onions, cause bad breath in both children and adults. Sulfur compounds settle in the mouth and are even absorbed into the blood.

For several hours after such a meal, the smell will continue to be released during exhalation.

Bacteria in the oral cavity “love” sugar and starch, so limiting these types of foods will go a long way in preventing bad breath and tooth decay.

Plaque on the tongue

Another extremely common cause of bad breath in babies, children and teenagers is the formation of plaque on the tongue. Odor-causing bacteria, food, and decaying skin cells often get stuck on the back of the tongue.

A white tongue is caused by debris getting stuck between the tiny tubercles on the tongue. Brushing the tongue every time the child brushes his teeth will help get rid of bad breath and white plaque on it.

Caries and dental infections

The cause of bad breath in a child can be caries. Bacteria that cause tooth decay emit odors. Food is more likely to get stuck in the damaged part of the tooth, and it is more difficult to clean it.

Odor can also cause problems such as mouth ulcers and dental abscesses. Usually, leftover food leads to these problems. Bacteria feed on these particles and plaque to produce hydrogen sulfide, which has a putrid odor.

Gum disease

Gum disease is associated with bad breath in people of all ages, especially children. Gum disease is inflammation and infection of the tissue that supports the teeth. Although children are unlikely to develop periodontitis, an advanced form of gum disease, they usually develop a less severe form called gingivitis.

With problems with the gums, the breath may smell of iron.

Gingivitis occurs when soft plaque and tartar (hardened plaque) build up on the teeth and under the gum line. Bacteria and toxins in plaque attack the gums, causing inflammation and persistent bad breath that doesn’t go away after brushing.

Infections usually smell bad, and gum disease is no exception.

Loose pediatric crowns or fillings

If a child’s dental crown or filling is damaged or flaking, food and bacteria can get under it. No wonder it causes bad breath in children.

Not enough saliva

Saliva helps wash away food and bacteria in the mouth and neutralizes acids that cause tooth decay.

At night, when children sleep, saliva production slows down, so they may have bad breath in the morning.

This type of bad breath is temporary and will go away when the child brushes their teeth and saliva starts flowing again.

Dry mouth can also cause bad breath.

When the mouth is dry, not enough saliva is produced, and food particles and bacteria settle on the teeth, creating an unpleasant odor.

However, unlike the first case, bad breath is not always temporary, as dryness can be caused by the consumption of certain medications or health problems.

Large tonsils

Children with large tonsils or tonsils with deep pits may have bad breath. This is because the tonsils become a magnet for the accumulation of food, bacteria and nasal secretions. Tonsil stones, called tonsillitis, can also form in the pits and give off an odor as they decompose.

Allergies or ear, nose, or throat infections

Viral and bacterial infections, such as strep throat, can cause bad breath.

Bacteria in the mouth feed on mucus and secretions that run down the throat and onto the tongue. Bacteria emit gases that smell unpleasant. Such conditions are often accompanied by a runny nose, nasal congestion and fever.

Mouth breathing

A study published in the journal Clinics found a link between mouth breathing and halitosis in children.

Researchers hypothesized that the mouth becomes dry because it is open all night, leading to bad breath in the morning.

Mouth breathing may be temporary and associated with nasal congestion, but it may be a child’s habit.

Certain health conditions

Diseases, in particular diabetes, gastroesophageal reflux, and in rare cases, problems with the liver and kidneys, can also make children’s breath stale.

A certain smell from a child’s mouth can indicate the presence of various diseases.

The smell of acetone (similar to the smell of nail polish remover) can indicate diabetes. In diabetes, the body either does not produce enough insulin or cannot use it effectively. Normally, insulin breaks down glucose in the blood so it can enter cells and provide energy. If the body can’t get energy from glucose, it starts burning fat as fuel instead. In the process of breaking down fat for energy, byproducts called ketones are released. Acetone is a type of ketone. If the breath smells like acetone, this indicates a high level of ketones in the blood, which can be toxic.

If the child’s mouth smells like ammonia, this indicates kidney disease. When the kidneys cannot remove all the urea, it breaks down into ammonia. Therefore, people with kidney problems often have breath that smells of chemicals or ammonia.

The smell of feces from the child’s mouth can indicate serious health problems, in particular, intestinal obstruction.

Also, a sweet smell can indicate liver problems or even hepatitis.

However, it is not necessary to make a diagnosis based on the smell of the mouth. As a rule, in severe diseases, bad breath is not the only symptom, so it is worth carefully monitoring the child’s health, and timely consult a doctor.

How to get rid of bad breath in a child

If your child has bad breath, peppermint drinks and breath-freshening chews or pills are not an option. They only mask the problem, not solve it.

Of course, it is important to find out the cause of the unpleasant smell and exclude the presence of diseases that can cause it.

It is also important to follow the following tips:

  • teach children to observe oral hygiene;
  • provide the child with a healthy and balanced diet;
  • make sure the child drinks enough water;
  • will teach the child to breathe through the nose;
  • visit the dentist on time, who will examine the child’s teeth and oral cavity.

When to consult a dentist about bad breath in children

If your child has a toothache or red, inflamed, bleeding gums, along with bad breath, schedule a visit to the dentist.

The child may have dental problems such as tooth decay or gingivitis that require treatment.

If bad breath is accompanied by a fever and other symptoms, consult a pediatrician.