Bad Breath


Our 3 year old daughter’s breath is often bad. What smells should we look for, are there any that we should watch out for?
Nicholas Godfrey – Oakville, Ontario

Dr. Greene's Answer

Most kids would go out of their way to avoid eating garlic or onions, yet it is not unusual for a child to wake up with very bad breath. Throughout the day, a child’s saliva, swished by the mouth muscles, washes away unwanted debris. As soon as a child falls asleep, saliva production plummets, and bad muscles relax. The longer a child sleeps, the higher the bacterial count in the mouth rises, resulting in “morning breath.”

Common Causes of Bad Breath

In children, smelly breath that persists throughout the day is most often the result of mouth-breathing, which dries out the mouth and allows the bacteria to grow. Children who consistently breathe through their mouths might have colds, sinus infections, allergies, or enlarged tonsils or adenoids blocking the nasal passages, so a visit to the pediatrician is in order. Thumbsucking or sucking on a blanket can also dry out the mouth. Tonsillar stones, collections of food and bacteria that get stuck in the crevices of the tonsils, can also cause bad breath.

Treating Bad Breath

To improve most cases of bad breath, the goal is to decrease mouth bacteria and increase saliva. The better your daughter’s toothbrushing technique, the smaller number of bacteria will be present. Make after-meal brushing a habit. Use a timer to help her brush for at least two minutes. Be sure she brushes her tongue. You might also try a rotary electric toothbrush. I do not recommend mouthwashes or fluoride rinses in young children, since they tend to swallow them. Breath mints may mask the problem, but don’t get at the source. As your daughter gets older, sugarless sour candy or sugarless chewing gum can get the saliva flowing and get those mouth muscles moving.

The American Dental Association (ADA) also recommends flossing at least once a day and increasing fluid intake. Some studies involving adult subjects suggest that commercially available tongue scrapers/cleaners may be slightly more effective than using a toothbrush to clean the tongue  However, studies using tongue scrapers/cleaners still need to be performed in children.

If the problem persists, she should see her doctor. Bad breath in children that doesn’t respond to the above measures should be investigated.

Uncommon Causes of Bad Breath

Here is a list of some very uncommon, but telltale, odors (mostly from Mace, Goodman, Centerwall, et al: The child with an unusual odor. Clinical Pediatrics 15:57-62, 1976). Take a whiff:

  • Acetone – diabetes or acetone, alcohol, phenol, or salicylate ingestion
  • Ammonia – some types of urinary tract infections, or kidney failure
  • Asparagus – eating asparagus (very unusual in children;>))
  • Bitter almonds – cyanide poisoning
  • Cat’s urine – odor of cats syndrome (beta-methyl-crotonyl-CoA-carboxylase deficiency)
  • Celery – Oasthouse urine disease
  • Dead fish – stale fish syndrome (trimethylamine oxidase deficiency)
  • Fresh-baked bread – typhoid fever
  • Foul – tonsillitis, sinusitis, gingivitis, tonsill stones, lung abscess, or dental cavities (some of these are actually quite common)
  • Garlic – arsenic, phosphorus, organic phosphate insecticides, or thallium poisoning
  • Horse-like (also described as mouse-like or musty) – phenylketonuria
  • Rancid butter – odor of rancid butter syndrome (hypermethionemia and hypertyrosinemia)
  • Raw liver – liver failure
  • Sweaty socks – odor of sweaty feet syndrome (Isovalryl CoA dehydrogenase deficiency)
  • Sweaty socks – odor of sweaty feet syndrome II (Green acyldehydrogenase deficiency)
  • Violets – turpentine poisoning

Three-year-olds often stuff items in their noses, and then forget about them. When my son Kevin was three, he put five peas up his nose before anyone found out! Watch for the combination of smelly breath and a smelly, yellow nasal discharge — especially from one nostril. You and I might not think of stuffing peas up our noses, but three-year-olds think outside the box!


J Am Dent Assoc, Effectiveness of mechanical tongue cleaning on oral levels of volatile sulfur compounds. 2001 Sept., Vol 132, No 9, 1263-1267 — Page last visited Oct. 11, 2019

Gen Dent. A Cochrane systematic review finds tongue scrapers have short-term efficacy in controlling halitosis., 2006 Sep-Oct;54(5):352-9; 360, 367-8 — Page last visited Oct. 11, 2019

Clinical Pediatrics The child with an unusual odor. A clinical resumé. 15:57-62, 1976 — Page last visited Oct. 11, 2019


Last medical review on: July 14, 2010
About the Author
Photo of Alan Greene MD
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
Get Dr. Greene's Wellness RecommendationsSignup now to get Dr. Greene's healing philosophy, insight into medical trends, parenting tips, seasonal highlights, and health news delivered to your inbox every month.
Add your comment

Recent Comments

My 4 years grand-daughter is got the bet smell, but every time in the morning,help me please there is a problem?

my son is 4+ age and he is having bad odour from his mouth even after brushing, also a bad odour from his urine, also sometimes he is having some kind of pain in abdomen and in night he use to make sound by tightening his teeth during his sleep. please suggest me what could it be.


This sounds like a great time for your son to get a physical exam.

If you’d like to conduct an at home test to find out what bacteria is in your son’s mouth and stool, you can get a home test kit from uBiome*. Of note, this kit is for the “Gut” and has a “Spare” test as well. For the Gut test, you simply wipe a swab on used toilet paper and swish it in the provided vial. You can use the “Spare” to test his mouth by swabbing his check and swishing the swab in the vial marked “Spare”. When you create your online account, be sure to label the “Spare” as “Mouth”. After both vials are ready, you mail them to uBiome in the included postage paid envelope.

Co-founder and Executive Producer,

*Note: Dr. Greene is the Chief Medical Officer of uBiome.

I have bad breath many years i use many bad breath products but no solve my problem l visited many dentists and ent specialist. And stomach doctor. They said everything is good l don’t know where bad breath comes lam very confused please help me what should I do.

You may have something wrong your tonsils or anoids in your throat. I had my tonsils removed and my foul breath went away.

i have bad breath since 8 years i have use all bad breath tips .its not helped i visited many dentist and ENT specialist they said everything is fine. please tell me what should i do

Is it possibly from the stomach? Try a bland diet for a week. See if it makes a difference. Your digestive system might not be performing up to standards and maybe needs a little rest. A bland diet consists mostly of steamed vegetables, steamed chicken and steamed potatoes. Apples without the skin and bananas. A pinch of salt and pepper, no other spices. Drink lots of water, no coffee, rather drink black rooibos tea with a teaspoon honey maximum twice a day. As a treat eat a half cup jello per day. Avoid milk, spices and red meat. Eat small amounts 5 times per day. Let me know if it made any difference after a week.

It happens often in kids when compare to adults. If your kid sleeps with her/his mouth open, sometimes, this situation can also be worse. New bacteria can easily find their way into your kid’s mouth when you kids opens his mouth. This is an optimum setup for these bacteria to work and reproduce them. This is one of the reasons for bad breath in children.

My 4 yr old has breathe that smells so bad it’s like death! It lasts all day long too. We brush and have children’s mouthwash that dad and I use on him to make sure it is done right. He has 2 silver caps and has a pretty good diet. He doesn’t shove anything in his nose nor does he have any breathing issues. His nose runs every now and then which I assume is allergies since dad and I have them pretty bad as well. But the smell persists so much that it makes me more nauseated than my pregnancy! He drinks throughout the day like a fish, eats pretty bland foods, has good dental hygiene, and no peculiar symptoms. :/ I’m so lost as to what it could be….

Everyone gets occasional bad breath though, so it’s not a big deal, just make … Should I tell my friend they have bad breath?

hellow.. Everyone gets occasional bad breath though, so it’s not a big deal, just make … Should I tell my friend they have bad breath?

I have a 3 year old girl with a very bad breath especially in the morning. Is there any remedy that I can do to help him

My three years and 8 month daughter has bad breath and bad smell in her urine in (at the same time). Sometimes there is not any bad smell in urine and mouth, but sometimes, after it starts again, it persists for few days. We noticed it two times. Please tell us! Is there any problem?

My 6 year old recently got metal caps on a couple of her teeth and sealants. Since her caps were put on, she has gotten very bad breath. It seems that every week it gets worse. When I floss between her capped teeth the foul smell is there on the floss. I asked her dentist but they never give me an answer although I tell them it didn’t start until the caps. Thet tell me maybe its her diet but I have been careful with that. Should I take her to another dentist for another opinion? I feel bad for her because kids can be mean and we dont know what to do about her bad breath.

Although I’m not a dentist … I am a dental assistant and I know that sometimes food can be trapped easily between crowns (caps) causing bacteria and a foul odor.
Especially silver caps on children … They do not have the most ideal fit like a lab fabricated crown that an adult would get .. I would do my best to keep them clean and floss daily maybe even invest in a electric toothbrush to help do the work.. Also “go betweens work amazing to clean interproximaly” – they are made by Butler Gum and come in different sizes .. You would most likely need ultra tight for a child … If the odor worsens or continues I would again take her back to the dentist and make sure the crowns are sealed good around the margins ( margins are where the crowns meets the tooth structure) because that would be the only other reason I can think of causing odor.. Especially if you are doing good home care and keeping them clean .. Keep up the flossing !
Good luck!

I have a 7 year old who has perfect teeth (other than them coming out like a normal 7 year old), but her breath is bad and she is getting teased in school!

Hi I’m having this same problem

I have a 6 yr old boy who always has really foul breath. We make sure he brushes well, so it isn’t hygiene. It seems to come from his throat. I am going to schedule him an ENT appointment to check his tonsils. I know food particles can become trapped in tonsils and cause a bad smell. Tonsil stones can cause very smelly breath.

My 3 year old boy have a very bad smell all say. He has three of his teeth decayed. His dentist suggested removal but I thought he’s too young to go through all that pain. Could it be the possible cause of the smelly breath because it’s all day. I’m confused please help.

I work as a dental assistant in a pediatric dental office. If you’re taking your son to a general dentist I suggest you take him to a pediatric dentist, because we would only recommend pulling out children as young as 3s teeth if the teeth were infected. If these teeth are infected there would be a bubble beside the teeth, or if there is large black decay that is too big for the tooth to be saved and the teeth will become infected. But yes, decayed or infected teeth would make your Child’s breath smell bad.

Just a quick question about my baby boy who is 10 months old. We have noticed that his breath smells like poo. I think it is genetic because I (the dad) have a problem as well. I’m a bit concerned as his breath seems too smelly all the time.

helloo, i have a kids with very bad breath, all day…he is 11years old…I take him to the dentist….brusth 2 time…..mouthwash…and bad breath cont

My grandson is 12 yo and brushes and glosses regularly,what could. Be some of the problems?