Unusual Breath Odors & What They Mean

Unusual breath odors are common in kids. Typically there isn't anything to worry about, but there are some breath odors that indicate an underlying problem.

Unusual breath odors are common in kids. Typically there isn’t anything to worry about, but there are some breath odors that indicate an underlying problem.

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.

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).

Unusual Breath Odors:

  • Acetone (fruity smell) – 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, lung abscess, dental cavities, tonsil stones, or gastroesophageal reflux  (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!

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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.
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Recent Comments

My husband’s breath smells like antifreeze. He is an alcoholic

Hi I don´t really know how to put this so i´m just going to say it…my Pastor breath smell very bitter all the time…i´m always wondering way?
And i know if I smell it everyone does.

Can somebody help me

My wife has a breath that smells like marijuana or digested grass. any ideas what may cause that?

craig and i smoked a jazz cigarette and now our breath smells like hot dogs, garlic on hot dogs. my teeth also patty lopez

I have been experiencing bad breath since Elementary school. I am currently 24 years old and still experiencing bad breath. It was first brought to my attention by my mom when I was younger. She embarrassed me a few times instead of helping me find out whats wrong with me. I have used all kinds of tongue scrapers including a spoon. I brush and floss twice a day as well as scrape my tongue. However, my breath still stinks. I have dry mouth a lot as well which cause my breath to smell like “poo”. It is really embarrassing. My son is 5 years old and he has told me my breath stinks as well. I know I am a very pretty girl but it doesn’t matter if my breath stinks. I hate to talk because I don’t want to offend anyone. I have tried chewing gum, mints, drinking water, taking vitamins. Nothing seems to help.

Same here! Totally ruining my life! I have tried everything and Nothing helps.

As someone else said probably tonsil stones. Try looking at your tonsils in the mirror with a flashlight. If you see white spots its likely stones. Get a waterpik so that you get flush out tonsil crypts. You would start on lowest level and maybe not go past 2. Some people use a finger to push their tonsils, also bobbie pins and q-tips. Water pik works the best I think. Besides that brush well, floss daily and get see your dentist 2x a year.

You probably need your large tonsils taken out. Bacteria could get stuck behind and rotten food. Have u gargled your throat?

you might have tonsil stones

What a bummer. Have you talked to your doctor about this? Maybe the issue isn’t your mouth, but your digestive system.

My wife and kids compliant that my breath sometimes smells like poop or sometimes like batteries, especially when I come back home after work. It is my mouth, sinuses or post nasal drip

Are you working around Nuclear Rocket Fuel? If so, thereyou go!

My mouth tastes like burnt popcorn or smoke. I don’t smoke and never around smoke. What could be causing this?

uhh thats a sign of a stroke…

Hi my breath smells like rusted nails and some times I can smell and taste it, I brush my teeth and use mouth wash two times a day, and some times three times a day. What could this mean, and should I be worried? I’m 45 by the way.

Hi my 9 month olds breath smells like sweet but stinky smelling poop n it just started about a day or two ago what do u think it could be

I hope your child is ok, as I see your question was posted in 2018. When my breath smelled like Poo, it was because my intestines had a bowel blockage. I had to have emergency surgery.

could need a brush and how sweet?my granddaughter is 9mo also x
patty lopez

My 2 yr old twin daughters but only ones breath smells like latex/acid since birth. No answers from the docs. No matter what she eats drinks or how many times she brushes. The smell is coming from within somewhere. Please help

Here my husband breath smells Like mustard and he didnt eat anything with mustard in it so can you tell me were it Come from tell me what to do so i can help him

he has to brush
patty lopez

I’ve never heard of anything like that. What time of day do you smell it or is it there all the time?

What causes breath to smell like a skunk or diesel fluid?

My son’s breath smells like blood

My 5 1/2 month old son has had a peanut oil smell on his breath recently. It comes and goes every so often. I breastfeed and we have been introducing baby foods. I have not ingested, nor have we fed him with anything with nuts. He is not exibiting any other signs or symptoms. I am trying to research what it might mean, but I am not seeing anything other than articles coming up for peanut allergies and such. What could the odor mean?

My breath smells like rubber, stinky feet, dead fish, and like something has rotten in my mouth. The same odor comes from my nose too. I had my tonsils removed in 2015 and my breath and nose still stinks. This is making me so depressed because when I see my Primary care docs or the ENT they also say they don’t smell anything. Suggested that I seek counseling.

probably tonsil stones. you can still get them without tonsils


I have been reading a lot of the posted questions and have now become curious….what is “oil pulling”? Enquiring minds just want to know.

Hi Connie,

Thanks for writing in.

“Oil pulling” has been used for a very long time. It’s very simple — place about 1/2 teaspoon of coconut oil in your mouth and swish it around for to to 20 minutes. Sometimes as little as five minutes will do the trick. When you’re done, spit the coconut oil into a disposable container (paper cups work well) and throw it away in the trash (not down the drain).

Typically for tonsil stones people do this a few times a day. It may take a week or so to see results. It is also hailed as a way to remove impurities.

I’ve done it myself, though I don’t have tonsil stones. It leaves my mouth feeling fresh and very silky.

I hope that helps enquiring minds ;)

Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

My daughter is 3, and it just stared today. Her breathe smells like a metallic smell. Almost like blood tastes in the mouth. I looked all in her mouth and I see nothing. Should I be really concerned? Any help would be greatly appreciated.

What causes me to smell and taste a musky smell all the time. Nasty

My husband’s breath at times smells like beef jerky. Even right after after brushing his teeth.

My breath smells like fish 🙃

My boyfriends breath smells like Marinara sauce. It’s not all the time. I’ve noticed this in men before. Any ideas??

Is your baby Italian?

My 3yr old sons breath and wee smells like coconuts and idea??

If it’s actually like syrup or waffles, see a doctor my dude

My son smell like a dead mouse frm his nose and mouth

What about the smell of burnt wires??

Does anybody know what the smell could be coming from when I kiss my boyfriend after he has had alcohol, I taste vomit with alcohol. it doesn’t really matter the amount he’s drinking. I don’t drink. It’s not the taste of the beer but if you were to mix beer with vomit

It might actually be vomit, if he’s been drinking beforehand.

Partner smells like bile

That’s a serious intestinal issue. Maybe even a perforation

My husbands breath smells like olives. I’m not sure how I got down to olives but that’s all I smell. He brushes his teeth but I still smell the odor. He hasn’t gone to the dentist in 8-9 years. I yell at him all the time for it. He does have nice teeth but they would be great if he went at least once a year, that’s all I ask. Help me out please!

My son’s breath smells like stale garlic. He and his Dad are upset with me because I stated we need find out what is the culprit. In fact, they’re not talking to me now. I told my son it could possibly be entomoeba gingivalis. He has been in college for 2 years and eats the dining hall food. I think there is something wrong and my spouse is upset that I said something about his breath. There has to be a root cause, his breath did not smell this way when he left for college 2 years ago.

my son is 21months old ad his breath started smelling like garlic this morniing. he was diagnosed with a brain tumor so we guess that tat is one of the effects of a brain tumor. could you maybe clarify if we need to see a gp asap

After 2 months, oral diabetic medications give me a chemical odor. It is so awful, at first I looked around to see what processing chemical I used, and to what I was exposing my pets. They call it a fruity odor but far from it. I feel like a walking Chernobyl. This is my 3rd intolerable medication. Suggestions?

My granddaughter’s breath smells like garlic no matter how many times she brushs her teeth and tongue.

My 8 year old son’s breath smells like burning plastic. When he was a baby his poops smelled the same way. It is really awful. Even after he brushes his teeth and tongue the smell comes back shortly afterwards. This bothers me greatly. It literally smells like someone lit plastic on fire. He is otherwise a healthy kid. Wondering what I am missing.

I Have a 2,5 Years girl that smells like fruit in her head, hair and behind her ears when she sweats. Her breath doesn´t smell like fruit neither her urine. Her diapers are quite normal and she doesn´t drink more water then the normal. She has a twin brother and he drinks more water then her. She acts perfectly normal for her age. What’s happening with her????

It sounds most like diabetic ketoacidosis.

Check her blood sugar


My breath smells of rubber, it comes and goes but what could be causing this? Please help

Hi Craig- your comment has come the closest to what I’m searching out. My BF’s breath smells like inner tubes from tires. I used to know someone with asthma who used an inhaler regularly, and his breath would smell like inner tubes from tires after using the inhaler. This current situation has nothing to do with inhalers though. You are the first person I found saying ‘rubber’ which seems the most similar to what I would describe. If you have found any answers, please feel free to email!

Why does my 2year old baby boy going to 3this coming june is suffering to bad breath it smells like a paste..the one that we used late 90s in a tube with diff.color.even i brush his teeth regulary..is there any problem with his health?because im worried.an advance thank you for those giving me the answer,.

My boyfriend’s breath ALWAYS smells like fish..during awake hours & after sleeping…I started thinking he was cheating on me with someone who doesn’t have good hygiene, if you know what I mean..lol..what could this be? He is 46 years old & he does dip tobacco

If it smells like Dead fish – stale fish syndrome (trimethylamine oxidase deficiency)

My 6 year old son is passing wind a lot and it smells of rotten cabbages, and his breath for some time smells like sick ? Any ideas ?? He brushes Twice a day

Sounds like an intolerance to dairy

My breath smells like medicine, what could that mean?

Why does my boyfriend’s breath smell like corn? Sweet and sickly.

Is he diabetic? If he hasn’t been diagnosed with diabetes, get him to have his glucose tolerance checked.

It could be ketoacidosis due to diabetes. Have him see a doc to check his glucose tolerance.

I’m dating someone who’s breath smells of corn it is the worst :(

My breath smells like cat piss, fish, [REDACTED], poop, idk what to do. Seven years suffering. Please help. Cost is not an issue for this cure.

Im not sure but you may have some candida issue, like a white pr yellow coated tongue, try to cut back on processed foods. Get yourself a tongue scraper its cheap out of walmart its called ora brush, careful with it you dont want to to brush your tongue too hard. If its candida, meaning yeast youre going to want to eat a lot probiotics found in yogurt or just get probiotics in pill form. Check with your doc if you have a deficiency in minerals or viatmins and go from there, also if youre intimate with your partner orally you may want to make sure that they are taking the same steps as you because if they have candida overgrowth which is found in our intimate parts too then can be causing the candida problem in your mouth. Pau D Arco is great at fighting this along with a diet that helps flush candida out. Grape fruit seed extract in pills helps keep that ph balance in check so ypu and youre special someone dont have that fishy odor coming from your intimate parts aswell too. Also Ms Greene is right oil pulling is great aswell, pulls toxins out from mouth

I had an issue like you after seeing several dentists….. I STILL HAD ongoing bad breath then I was treated for tonsil stones …..had my tonsils removed at age40 see an ENT SPECIALIST NO MORE BAD BREATH!!GOOD LUCK!

Hi Andrew,

I’m sure you’ve tried everything that has been suggested, but it would help if you could list them. For instance, have you tried oil pulling?

Hope we can help.

my breath smells like peanuts and feels like its coming from my stomach

My daughter has a sweet smell coming from her mouth shes had it before

I am 60 years of age and my breath smells like I eat garlic.what can I do

My breath smells like raw meat, well that’s the only way I can describe it, but mostly only when I wake up. It’s annoying and worrisome. What could it be?

Its quite normal to wake up with bad breath because when you sleep for hours, that’s long enough for your body to get a little dehydrated. When you are dehydrated, you would have less saliva which helps to wash away odor-causing bacteria. In other words, its ok to wake up with smelly breath. Normally, people who are pregnant are most likely to experience bad breath which smells like raw meat.

My 12 yr old daughters breath smells like urine. Should i be worried?

my grand daughter breath smells very different ; odd and when she breath though her nose you can smell her breath ! what is the problem ? is that something I should worry about ?

NOTE: I am not a doctor and I am a mom.

I wonder if you’re smelling this odor when she breathes through her nose if if could be a sinus infection. Probably worth having checked by a doctor.

Executive Producer DrGreene.com

breath smells like shoe polish……and times can even smell fish…..

i have chronic bad breathe that smells like garlic. I don’t eat garlic at all because of this. What can I do? Breath mints n mouth washes don’t seem to work and neither do gum and mints. I brush me teeth n have good oral hygiene. Please help.

People tell me my breath smells like alcohol, and I don’t drink. It’s embarrassing. Any explanation for this? I am 33years old by the way.

Hi:) I’ve been a Registered Nurse for 13 years and your comment stood out…have you had your blood sugar tested? Diabetics who are in ketoacidosis will have breath that smells like that of an alcoholic. I would definitely see a doctor because your health could be at risk. (not trying to scare you! But I think you should schedule a visit;))

Whenever I chew sugar free gum, my breath and mouth smell like popcorn, and I never eat popcorn. I brushed and used mouthwash. And, still keeps smelling. What should I do???

I brush everyday but my breath smells like popcorn why….

dont chew sugar free gum duh

My 9 month-old daughter’s spit smells almost vinegary. Her hands and cheeks smells like the spit because she chews on them. Her pacifier, toys, etc. smell like her spit. The dried spit on her face is flaky and white. What is going on? I brush her gums twice a day with baby tooth paste and rubber finger.

How can I fix this?

Brushing her gums is good. But if you want excellence you must brush her tounge as well. Bacteria (germs) hide in the tounge I like to think of it as a rug or carpet where all the dust mites are at. As far as her spit ( saliva) it itself does not have a smell (odor) but when it does is when it comes into contact with bacteria. So now she is nearly two I think you can use regular toothpaste on her gums or teeth and tounge especially. Good luck. I hope this helps.