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Why Does My Baby’s Pee Smell Like Ammonia?

You’re changing your little one and suddenly you get a whiff of ammonia. You smell around the room and notice that the smell is central to your little one.

A small investigation leads to the conclusion that your baby’s pee smells like ammonia. This can be caused by anything from specific foods and vitamins to bacteria or an infection.

It’s important to learn the causes of this, how to prevent it, and when to call the doctor to make sure that your little one is safe. 

Make Sure It Isn’t The Cloth Diapers

Sometimes, you can think that your little one has pee that smells like ammonia when it’s really just the cloth diapers you’re using. There are several things that can lead to cloth diapers having an ammonia smell.

A build-up of detergent on the diaper is one thing that is known to result in them smelling like ammonia. Mineral build-up from hard water, well water, or any other water that has a high content of minerals in it is another common cause.

You could also not be getting your diapers as clean as they need to be, resulting in an odor. These are all common reasons you could smell ammonia during a diaper change. 

To make sure that it isn’t your cloth diapers, wait until you wash a batch. Then, take a whiff when they are dry. If they have a faint ammonia smell, it’s the cloth diapers. If not, it’s your little one’s pee.

Baby’s Urine Smells Strong Like Ammonia?

It’s extremely common for a baby to have urine that smells like ammonia. There can be quite a few different causes.

It’s important to accurately determine the cause so that you can make sure that your baby is healthy, and to ensure that they do not continue to smell like ammonia. 

Urinary Tract Infection

When bacteria gets in your little one’s urinary tract, it results in the same bacteria being present in their urine. This can make their pee smell like ammonia.

baby crying

It’s not common for babies to have a UTI, but they’re pretty easy for babies to get. Diapers are full of bacteria when soiled, making it all too easy for that bacteria to get into other places.

Other signs of a urinary tract infection include: 

  • Strong smelling urine
  • Cloudy urine
  • Bloody urine
  • Fever
  • Excessive crying that is not otherwise explained

A urinary tract infection can cause severe kidney damage if left untreated. If you are not sure why the baby pee smells like ammonia, it can’t hurt to take them to the doctor to double-check. 


Most smaller children get all of the fluid that they need from a bottle. Older children that are on baby food might not get enough liquids if they are eating a lot of baby food.

During hotter months when little one’s sweat, it can lead to dehydration. Other common causes of dehydration include: 

  • Diarrhea
  • Vomiting
  • Illness, such as a cold
  • High fever
  • Hot weather

If you’re concerned that your baby’s pee smells like ammonia due to dehydration, watch for these other signs and symptoms: 

  • Dry skin
  • Cracked lips
  • No tears when crying
  • A soft spot appears sunken in
  • Dark yellow urine
  • Less than six wet diapers in one day

If you notice any of these signs, contact your pediatrician immediately. You can also pick up some Pedialyte to give your little one to help hydrate them. 

Certain Foods

If your little one is beyond trying one baby food at a time and you’re finally feeding them plenty of solids, you can expect to see quite a bit of diversity in their poop and pee. Specific foods are known for making a baby’s pee smell like ammonia.

certain foods

These include: 

  • Foods high in protein, like eggs
  • Asparagus
  • A lot of Vitamin B
  • Brussel sprouts

Other foods might make urine smell, but these ones are known for making it smell like ammonia. If your baby’s pee smells like ammonia, try switching their diet if you like. If it’s caused by foods, however, it’s rarely a reason for concern. 

Why Does My Breastfed Baby’s Urine Smell Strong?

If your little one is exclusively breastfed, you’re already well aware that it can’t be food causing the strong smell. It might still be due to the above mentioned (dehydration, urinary tract infection) though.

In addition to those reasons, there are a couple of other things that can lead to a breastfed baby’s urine smelling strong. 

Not Drinking Enough Milk

If your little one is not eating enough when they are feeding, it can lead to their urine to be more concentrated. This can also result in your baby’s pee smelling strong.

When you breastfeed, it can be hard to measure how much your baby is drinking. Keep an eye on your little one for signs of dehydration, and make sure that your baby is eating until they are full.

baby bottlefeeding

Lactation experts in your area can provide further assistance if you’re having a hard time breastfeeding.

Something You Ate

While your baby may be exclusively breastfed, you’re still getting a wide range of food in your diet, and this is being passed on to your baby via breast milk.

If your diet is rich with foods like garlic, onions, or asparagus, this could be the culprit. These foods are well-known for being the reason that baby pee smells strong. 

It’s Normal

As your baby gets older, it’s normal that their pee smells a little bit like ammonia. If your baby is otherwise healthy, there is more than likely nothing to be concerned about.

However, it’s still a good idea to check with your pediatrician to make sure that your little one is not suffering from an infection. 

Does Your Baby’s Pee Smell Like Poop?

Baby pee that smells strong like poop can be both confusing and alarming. Sometimes, it’s perfectly normal, though. Double-check for these things to find the reason that your little one’s pee smells so strongly. 

Something You Ate

If you freeze breast milk, it could easily be something that you ate. However, if the breast milk was pumped four weeks ago, you might not remember exactly what you had to eat that day.

Foods are a well-known cause for leading to foul-smelling urine. Likewise, if your baby is on solid foods, it could be something that they ate. 


We don’t always hear it when our baby passes gas, and some of them have the potential to clear an entire room. If your baby passed gas right before you changed the diaper, or they are known for having excessive gas, it could easily be a silent fart.

Sometimes, the smell seems to get trapped inside of their diaper, so you smell it when you take the diaper off. 


Vaginal infections can have a smell that can be described as smelling like feces. Urinary tract infections are known for making a baby’s pee smell like ammonia, but they can also cause it to smell like poop.

diaper change

If your baby’s pee smells like poop, it could be an infection. Contact your pediatrician to double-check. 

Baby’s Urine is Smelly Like Vinegar

Babies can’t always tell us what is wrong, which is why it’s important to keep an eye out for anything that seems out of the ordinary. If your baby’s urine is smelly like vinegar, that’s a sign that something is off.

It could be any of the things mentioned above, such as something you ate or a urinary tract infection. It could also be a sign of dehydration (remember to check the color of the pee to double-check for dehydration).

If none of those fit, or your pediatrician has ruled out a UTI, these other common things could be the reason. 

Scented Diapers

If you recently switched diaper brands, it could be the diaper itself instead of the urine. Sometimes, the smell of your little one’s pee mixes with the scent of the diaper to create a less than pleasant smell.

This is a common reason for noticing a vinegar-like smell when changing your baby’s diaper. 


This a common sign that your baby is not feeling well. It could indicate an infection, such as a UTI. This smell could also mean that your little one is coming down with a cold.

If your baby is already sick, this is more than likely the reason why you are noticing a vinegar smell. Keep an eye on it, and give your doctor a call if it does not subside on its own. 

High Lactic Acid Or Acid Reflux

Both of these result in more acid in their belly, which results in their bodily fluids smelling a bit sourer, from their breath to their urine. If your little one has acid reflux, you might see this come and go for months.

Likewise, if you have done anything that might increase the amount of lactic acid in your breast milk or naturally have more, it’s normal to notice this smell as well.

For example, probiotics are known for increasing levels of lactic acid. Smell your breast milk to determine if it smells sour. If it does, that’s why your baby’s wet diapers smell like vinegar. 

When you notice that your baby urine smells strongly of poop, vinegar, or another odor, always remember that it can be normal or a sign of something abnormal.

Look through possible causes to determine the root of the problem and give your little one’s doctor a call just in case.