Formula Fed Baby Gas Smells Like Rotten Eggs – What to Do

By Maria Wilcox •  Updated: 10/31/22 •  8 min read
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Breast milk is not always an option so sometimes we have to use formula. If you notice a formula fed baby gas smells like rotten eggs, it is likely that the issue has garnered your attention – quickly. Sulfur-smelling gas isn’t pleasant for anyone. But aside from simply smelling foul, your baby’s gas might be pointing to something that needs to be addressed concerning your baby. 

Interested to know what factors might be causing excessive gas in your little one? If so, then stay tuned. We’ve got the answers you need and more in today’s post.

Why Does My Baby Smell Like Eggs?

A baby that smells like eggs, or rotten eggs to be exact, may have causes that aren’t indicative of anything serious. This can sometimes happen with formula-fed babies.

Like adults, babies experience gas as a normal part of daily life. 

When excess gas builds up in our systems, the gas has to escape one way or another. This can happen through farting or burping.

Still, if your baby’s gas seems excessively strong, you may want to do a bit of investigating to see what’s up. A lot of times, foul-smelling farts are a result of digestion issues.

However, there can be other causes for strong gas as well. 

formula fed baby gas smells like rotten eggs

Consider the following reasons your baby may have gas that smells like rotten eggs:

Under-Developed Digestive Systems

When babies are born, they naturally have immature digestion systems which can slow down the rate at which foods are digested. 

As your baby’s body grows and develops, he or she will be able to tolerate more things in their diet, but for now, even milk may be a struggle, especially if the milk is baby formula rather than breast milk

Therefore, if you notice that your very young baby has a lot of gas following his or her feeding session, it may simply be that his or her digestive system isn’t mature enough to handle that at this time.

As the months go on, however, this issue may just remediate itself. 

Drinking Too Fast

Along with immature digestive systems comes the possibility that your baby is simply drinking his or her milk from the bottle too fast. 

Quick and frequent gulping of milk is a surefire way to introduce gas to the stomach, and as a result, you may find your baby belching and gassing much more than you expected. 

If you notice this to be the case, be sure to check the flow of the nipple on the bottle you are using to ensure that it is the correct flow for your baby’s age. 

nfant | Slow Flow Nipple, Purple (6ml/min), 4-Pack

Flows that are too fast will cause a baby to gulp too quickly which can thereby cause gas. Moreover, excessive and frequent galloping can have a negative impact on your child’s feeding experience. 

Note: Another reason some babies may be drinking and gulping their milk too fast is that they are very hungry. To prevent this, try to learn your baby’s hunger cues so that he or she isn’t getting too hungry between feeds causing him or her to hungrily gulp their milk at each feeding.

Crying Too Much

Yes, we all know that infants cry. But too much crying can lead to excessive air being taken in. While there isn’t always something you can do about an infant crying, you can at least cover your bases to ensure that your child is okay. 

Be sure to check your baby’s diaper, feeding schedule, and comfort level in order to assess what may be going on with your child. If your baby wants to be held, consider purchasing a baby wrap to keep your baby hugged close to your body. 

This will help comfort your baby throughout the day, but will also keep your hands free.

Boba Wrap Baby Carrier, Grey - Original Stretchy Infant Sling, Perfect for Newborn Babies and Children up to 35 lbs

Sensitivities to Formula

Does cold formula cause gas?

Sensitivities to formula, or more specifically, cow’s milk protein are common causes of rotten egg-smelling gas and tummy troubles in general. 

Because a baby’s digestive system is already sensitive, feeding your baby a bottle of cow’s milk can be quite harsh on the stomach, as there are even many adults who do not handle cow’s milk well.

If you suspect that it is your baby’s formula causing these woes, be sure to do your part by following up with your pediatrician. He or she can guide you to better formula-feeding options that can hopefully provide your baby with a little relief. 


Lastly, it could be that your baby is experiencing gas because he or she has constipation.

Baby has smelly gas but no poop? Sometimes, it may be that your baby is having difficulty pooping but can still release gas.

If this is the case, look for other signs such as your baby not pooping for more than five days, crying while pooping, and having blood-streaked stools, as these are all indicators of constipation. 

(Have you heard that orange juice is used for baby constipation sometimes?)

formula fed baby gas smells like rotten eggs

Why Does My Child’s Gas Smell Like Rotten Eggs?

Toddler Fart Smells Bad

Though toddlers have more developed digestive systems than young infants do, they are still susceptible to tummy troubles just as much as adults. Therefore, a toddler whose farts smell bad is usually the result of poor digestion or may be a negative reaction to something they ate. 

Sometimes, lactose intolerance can crop up later in life, and therefore, if you notice that your toddler is particularly gassy after consuming dairy products, you may need to speak with your doctor about the possibility of lactose intolerance. 

Other foods besides dairy your toddler may be eating that may be causing his or her to have strong-smelling gas include:

  • Cabbage
  • Broccoli
  • Brussel Sprouts
  • Beans

Baby Has Smelly Gas and Green Poop Formula-Fed

Baby Has Smelly Gas and Green Poop

Green poop is relatively common in formula-fed babies, especially if the formula they are consuming is iron-fortified. Still, the accompaniment of green poop with strong-smelling gas may still indicate that something is off, especially if green poop and gas aren’t typically the norm for your baby. 

Refer to some of the aforementioned possible causes of foul-smelling gas to narrow down which might be the reason for your baby’s tummy woes. Of course, if these symptoms really concern you, you should seek help from your pediatrician for tailored advice. 

Why Does My Child’s Gas Smell Like Rotten Eggs? Could Be Their Diet!

If your baby has gas that smells like rotten eggs, do your best to narrow down the causes. Oftentimes, it is an issue with the digestive system that is causing the gas, but these digestive issues are usually benign. 

Still, if the gas continues and your baby seems to be uncomfortable, be sure to reach out for help from your local pediatrician for more guidance. 

Formula fed baby gas smells like rotten eggs – FAQs

My 2 day old newborn smelly gas…What does it mean?

A baby this young that has smelly gas may be because he or she isn’t used to the baby formula they are being fed, or if the baby is breastfed, it could be that he or she is reacting to something in the mother’s diet. To be sure, contact your pediatrician for help, especially if the strong-smelling gas continues. 

Is It Normal For Baby’s Poop to Smell Like Eggs?

It can be normal for a baby’s poop to smell like eggs sometimes, but it is usually an indicator that something is wrong with his or her digestive tract.
Rather than brush it off, do your best to get to the bottom of what is causing it. 
For help determining the causes, look to the aforementioned reasons babies often become gassy listed in the segment above.

Maria Wilcox

Former instructor with an M.A. in Education turned grateful stay-at-home mama to one, I look to share helpful insights related to babies, toddlers, kids, and families for the benefit of real people just like you.

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