Why does my toddler have bad breath?

Some morning breath is normal at any age, including for toddlers, because saliva flow drops during sleep. Bad breath through the day is less normal and usually has a cause you can find. This page is about children roughly 1 to 5 years old. For babies, see our guide to bad breath in babies.

Bad breath is common in children overall. In a study of Japanese school children, about 45% had measurable bad breath, and the amount of coating on the tongue was the strongest predictor. That study was in older children, but it shows how much the tongue matters even at a young age.

Toddlers often breathe through their mouths when their noses are blocked. Cleveland Clinic explains that in children, swollen or infected adenoids or tonsils can block the airway, and that chronic nasal congestion makes mouth breathing more likely. Mouth breathing dries the mouth and is linked with bad breath; studies of children have found a significant association between mouth breathing and bad breath.

Signs to watch for include snoring, restless sleep, breathing pauses or gasping at night, and constant open-mouth breathing during the day. Cleveland Clinic advises seeing a provider if your child often breathes through their mouth. Treatment depends on the cause and may include allergy treatment or, sometimes, surgery to remove the adenoids.

Curious toddlers sometimes push small things such as beads, food, bits of toys or paper into their noses. MedlinePlus notes the object can stay there unnoticed for a while, and that symptoms include foul-smelling or bloody nasal discharge, difficulty breathing through one nostril and irritability. MedlinePlus lists an object stuck in the nose, usually in children, among causes of bad breath.

Do not try to dig it out with cotton swabs or tweezers, which can push it further in. Take your child to a doctor. MedlinePlus advises getting medical help right away if the object is sharp, a button battery or paired disc magnets, if your child cannot breathe well, or if you cannot easily remove it.

• Brush twice a day, with you doing or supervising it. HealthyChildren, from the American Academy of Pediatrics, advises a rice-grain-sized smear of fluoride toothpaste until age 3 and a pea-sized amount from age 3, and supervising brushing until children can do it well, usually around age 10.
• Brush the tongue gently with the toothbrush at the end of brushing. A soft toothbrush is enough at this age.
• Make brushing the last thing before bed, with no milk or juice afterward, only water.
• Offer water through the day, especially in hot weather or when your child is unwell.
• Keep the nose clear during colds so your child can breathe through it, using saline drops if your doctor or pharmacist suggests them.
• Book dental visits. HealthyChildren advises seeing a dentist by the first birthday.

See a dentist if you see spots or holes in your child's teeth, or bad breath continues despite good brushing for a couple of weeks. See a doctor if bad breath comes with discharge from one nostril, snoring with breathing pauses, fever, a sore throat with trouble swallowing, or if your child seems unwell.