A small amount of mucus in a baby’s poop is not usually a problem unless other symptoms are present. However, a lot of mucus, mucus in several stools in a row, or mucus with diarrhea may indicate an allergy, infection, or other problem.

The intestines naturally secrete mucus that helps coat the intestinal tract, digest food, and pass stool. Occasionally, some of this mucus ends up in poop. A small amount of mucus in one or two diapers, especially with no other symptoms, is usually not a sign of illness.

Sometimes, mucus appears in large quantities or recurs for several days. In this case, there is more likely to be an underlying issue. Here, we examine some of these causes and explain when to contact a doctor.

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Bacterial, viral, and parasitic infections can alter intestinal processes and cause mucus to pass into the stool. This may accompany diarrhea.

Diarrhea

Mucus may be more visible in loose stools. It is common for infants to have loose stools, so it can be difficult to tell the difference between regular stool and diarrhea. Some signs of diarrhea include:

  • more frequent bowel movements than usual
  • signs of pain or distress, such as crying, tensing the body, or making unusual movements
  • a decrease in urination that may signal dehydration

Diarrhea often goes away on its own, so ensure that the baby drinks plenty of fluids to prevent dehydration. Caregivers of babies who only chestfeed need to make sure that there are frequent feedings.

Prolonged or severe diarrhea in infants under 3 months of age can quickly cause dehydration and further complications. Call a doctor if:

  • a baby shows signs of dehydration
  • diarrhea lasts more than 2 to 3 days
  • if diarrhea is very severe

Allergies and food sensitivities can cause diarrhea or lead to mucus in a baby’s poop, though this is uncommon. In babies who chestfeed, a sudden change in the breastfeeding parent’s diet may be the cause. Sensitivities to iron, soy, or other formula ingredients may also play a role.

In older babies who eat solids, certain foods can cause diarrhea. This could be an early warning sign of food sensitivity, though it is common for poop to change in color or consistency as parents and caregivers introduce new foods.

Sometimes, a sudden change in a baby’s diet, such as switching to a new formula, can cause diarrhea for a few days. Talk with a pediatrician about managing these dietary changes to minimize the risk of diarrhea and stomach pain.

Chestfeeding changes

Changes in the way that a baby breastfeeds can affect the texture of their poop. For example, some babies who feed briefly before switching breasts have frothy green stools.

If a baby breastfeeds, their stool may seem to contain mucus. This can occur when they get more foremilk than hindmilk. Foremilk is the milk available at the beginning of a feed and can be thinner and sweeter, while hindmilk is available at the end.

Feeding on each breast for longer periods may help.

A baby may have blood and mucus in their stool. If the stool is very hard, this could mean they are constipated. The blood and mucus could come from tiny tears in the baby’s anus. Ensuring that the baby consumes plenty of fluids may help.

Call a doctor if there is:

  • extensive bleeding — more than just a few streaks in the stool
  • bleeding that appears in several bowel movements
  • bleeding that disappears and comes back a few days later
  • diarrhea with blood (with or without mucus)

If a baby poops only blood and mucus or has lots of blood in their poop and is fussy, go to the emergency room.

Rarely, mucus in a baby’s stool can signal a serious problem.

If the stool looks very fatty and is unusually large or foul-smelling, the issue could be steatorrhea, meaning there is too much fat in the stool.

Numerous conditions can cause steatorrhea. They include:

  • Liver health issues: A baby with liver health problems may have yellowish skin and eyes and dark or infrequent urination. In rare cases, the baby’s stool may also turn pale or white.
  • Pancreas health problems: When the pancreas does not work correctly, the body cannot properly absorb or digest fat. The baby’s stool may also be pale or white.
  • Malabsorption diseases: Some diseases make it difficult for the body to digest fat. In babies who have begun eating solids, celiac disease or cystic fibrosis, for example, may be a factor.

If there is only a little mucus in the baby’s poop, it is usually safe to wait and see if it goes away.

However, call a doctor if the baby:

  • has a lot of mucus in their stool
  • has other symptoms, such as diarrhea, a fever, or pain
  • was born prematurely or is under 3 months old
  • has a weak immune system because of a disease or medication

Anyone unsure whether there is a serious problem needs to exercise caution and call a pediatrician.

Go to the emergency room if the baby:

  • has large quantities of blood in their stool
  • has white stool and seems ill
  • shows signs of dehydration, such as chapped lips, sunken eyes, or infrequent urination
  • stops eating or feeding

A baby may have other types of stool, such as:

  • Meconium: This is a black or dark, sticky stool that babies pass shortly after birth. Talk with a doctor if it occurs for more than 3 days.
  • Healthy poop: In infants, this is usually soft and may be slightly runny. Babies who breastfeed tend to pass yellowish, seedy poop. Healthy poop can also be brownish-green or thick and tan.
  • Brightly colored stool: When a baby begins eating solids, certain foods can change the color of stool. Carrots, for example, may turn stool red or orange, while spinach may turn it green.
  • Constipated poop: This may be dark brown, lumpy, and hard.
  • Black stool: This can signal bleeding in a baby’s upper digestive system, so contact a doctor.

What does mucus in a baby’s stool look like?

Mucus in the stool may appear jelly-like or stringy. In some instances, it may appear clear but may also have a white or yellow hue.

What causes blood and mucus in a baby’s stool?

Mucus in the stool can occur due to natural digestive secretions but can occur due to responses to allergies or infections. Blood in the stool may indicate bleeding around the anus or more serious internal occurrences such as stomach ulcers.

Most changes in a baby’s poop are temporary, and a small amount of mucus in stool is usually no cause for concern.

However, a pediatrician can offer reassurance and help monitor the baby’s symptoms. A parent or caregiver who is unsure whether changes in stool indicate a problem needs to contact a healthcare professional for guidance.