Baby Poop and Gut Health

Snapi Health
5 min readJan 25, 2022

As fun as they are to talk about, number two’s are an important topic because they give insight into a baby’s overall health. Essentially, a baby’s poop is reflective of their gut’s health: emerging research is finding links between good gut health and regular stooling. One study found that stool consistency is strongly associated with bacterial richness in stools, and thus a healthier gut. This is also why our Microbiome Test Kit specifically tests your baby’s poop — their stool provides valuable information about their gut health. To read more about gut health and the microbiome, check out our previous articles!

As a new parent, you may have found yourself asking or googling the question “Is this normal?” about your newborn’s number two’s. That’s because there can be some really shocking colors, textures, and smells — naturally, you’re concerned if these stools are normal or not. Fortunately, there are some normal patterns that baby poop follows. We’ve broken things down to help you know what to expect (and what not to expect) in your baby’s stools.

Normal Infant Stools:


Newborns only pass one stool in their first day of life. Their first stool will be a tar-like, black or dark green stool that’s called meconium. Meconium is completely sterile, so it doesn’t have a bad smell. This first poop is normal in a baby’s first 24 hours of life.

After a few days of life

Around day four, a baby’s stool becomes lighter in color and has a less sticky texture. In the early weeks of life, an average of four stools per day is typical; this usually decreases after six weeks. Stool frequency is incredibly variable and is influenced by what kind of feedings a baby gets, how old a baby is, and other factors — similar to what influences a baby’s microbiome diversity. Expect your baby’s stooling patterns to change as they grow.

Breastfed vs formula-fed

As babies’ diets change, so does their poop. Breastfed babies pass yellow- or green-tinted, looser stools. They often poop after every feeding, though this varies by baby. Formula-fed babies often have slightly firmer stools and the color varies; it depends on the formula. Generally, earth-tone colored stools (yellow, green, brown) are healthy stools. Babies consuming formula don’t typically poop after each feeding the way that breastfed babies do, and this is normal as well. A combination of both breast milk and formula will produce a fusion of the stools described above, and it introduces a large variety of microbiota to baby’s gut.

Complementary solid foods

Once solids are introduced, a baby’s stool color gets less consistent. The stool color is sometimes reflective of what they ate — so a blue-tinted poop after the baby ate blueberries is not concerning! Moving from an all-liquid diet to introducing solids means several things: firmer poops with more bulk, lower frequency of poops, and smellier poops. Solid foods provide more bulk than liquids do. Plus, now your baby is getting some fiber in their diet from solid foods. Fiber helps firm and bulk up their stool, keep their digestive tract flowing, and fuels cells in baby’s colon (aka improves baby’s gut health!) The new smelliness is a result of new gut bacteria from solid foods, which is great for developing a baby’s gut health but not so fun for the diaper-changer.

A baby’s digestive tract is much shorter and less developed than an adults, so solid foods have less opportunity to get digested. As a result, sometimes you’ll find little bits of undigested food in their stool which is completely normal. High-fiber foods like corn and carrots are the usual undigested suspects.

Not Normal (when to be concerned about baby’s stools):

There are a few textures and colors to look for in dirty diapers. The two textures are either runny, watery poops (diarrhea), and firm, dry poops (constipation). Diarrhea usually happens when a baby is sick from bad bacteria, a virus, or is taking antibiotics. Watch for frequent, very watery stools; keep the baby hydrated since they are losing a lot of fluids via stooling. Constipation looks like small, dry, pellet-like poops. Babies are usually upset because these stools are difficult and uncomfortable to pass. Bottle-fed babies are more likely to experience constipation when formula is mixed with too little water. Similar to diarrhea, hydration is important to relieve constipation. Both diarrhea and constipation usually resolve themselves; if these conditions are ongoing after a couple days, or your baby has a fever or is vomiting, see your pediatrician.

There are two stool colors that should signal you to visit the pediatrician immediately:

  • Dark red or black stools. These colors are a sign of a very serious problem, likely internal bleeding. Blood appearing in the stool could be due to an infection, a milk allergy, or bleeding in the digestive tract for other reasons.
  • White stools. Often also chalky in texture. Stools get their color from bile, which helps digest food; bile is made in the liver and stored in the gallbladder. These stools may be a sign of a liver or gallbladder problem.
  • See your pediatrician right away for these concerning colored stools.

There’s more where that came from…

Subscribe to our weekly newsletter to receive articles from our dietitians at Snapi Health. Make sure to follow us on Instagram @SnapiHealth and shoot us a DM with any questions you may have!


  1. Mohrbacher N. Diaper Output and Milk Intake in the Early Weeks. Breastfeeding USA. Published September 6, 2016. Accessed July 21, 2021.
  2. Vandeputte D, Falony G, Vieira-Silva S, Tito RY, Joossens M, Raes J. Stool consistency is strongly associated with gut microbiota richness and composition, enterotypes and bacterial growth rates. Gut. Published January 1, 2016. Accessed July 21, 2021.

About the Author

Dana Schechner is a Registered Dietitian Nutritionist and Lactation Consultant who is passionate about sharing credible, science-backed information. Dana is a true foodie!

#baby #momlife #newborn #babyfacts#babylove #parenting #babyshop #motherhoodunplugged#parenthood #sahm #newmom #infant #honestmotherhood#babyfood #dietitian #babyledweaning #parentingtips#babyblog #newparents #microbiome #babygut#momminainteasy #realmotherhood #motherhoodmoments#motherhoodunited #newdad #candidmotherhood#babycare #babyhealth



Snapi Health

The only diet made 100% for your baby. Backed by science, delivered by dietitians.