Just like adults, babies can have different-smelling gas patterns that often depend upon what baby has eaten (or what mom has eaten and passed along in her breast milk).
The key to decoding your baby’s gas is to first identify your baby’s “normal.” Over the course of a few days, determine about how often your baby passes gas. Your next task may not be as pleasant, but it is to determine what the typical smell of your baby’s gas is.
Gas actually consists of several different gases, the most of which is simple carbon dioxide, plus other gases that don’t have a smell. These include hydrogen, methane, nitrogen and oxygen.
However, it’s the gas that is present in a very small amount that can make the greatest smell: sulfur. Sulfur gas is commonly compared to a smell similar to that of rotten eggs.
The smells your baby produces via his or her gas are typically the healthy by-product of breaking down compounds found in breast milk or formula. However, here are some variations that can help you determine normal versus something worth calling her pediatrician about.
No smell at all
Infant gas comes from two sources: swallowed air, which occurs due to crying, and the breakdown of foods in your baby’s digestive system. This means that sometimes when your baby passes gas, you won’t smell anything at all. This is a normal finding that you can regularly expect to hear—but not smell—from your little one.
Mild, sulfur-like smell
Certain foods are known to contain higher compounds of sulfur. These include beans and vegetables, especially broccoli, Brussels sprouts, and cauliflower. If you are breastfeeding your baby and have enjoyed these or other veggies, you may notice your baby has a mild, sulfur-like smell to her gas. This typically goes away fairly quickly and shouldn’t be overly offensive on the whole.
Strong, sulfur-like smell
Gases from the breakdown of vegetable compounds are likely to produce more gas in the digestive system because these compounds also contain fiber and starches. While these produce more gas, a diet high in meat compounds tends to produce smellier gas because red meat contains higher amounts of sulfur compounds. This means that if your baby’s gas is especially sulfur-like, high-protein foods could be the culprit.
If your baby’s gas falls more into the foul or sour category than a strong, sulfur-like smell, this could be an indicator of either an infection or poor absorption of some nutrients, especially lactose. If you have consumed dairy or milk products and feed your baby or if your baby’s formula contains lactose, this could be something worth discussing with her pediatrician.
If you can’t link the gas with a particular food, it’s possible your baby may be experiencing a stomach infection. Watch him or her for other signs of infant gastroenteritis, such as a change in the amount of both gas and stools, vomiting, poor feeding, and fussiness. Fever can be present or absent in gastrointestinal infections. Fevers over 100.4 degrees Fahrenheit in an infant less than 3 months old should be evaluated by a doctor.
Reviewed by Dr. Sara Connolly, April 2019
- There are many different kinds of gas smells, so determine what your baby’s “normal” smell is.
- Sometimes, when your baby passes gas, you may not smell anything at all.
- If you can’t link the gas with a particular food, your baby may be experiencing a stomach infection.