what causes a breastfed baby to have diarhhea

Most babies have 1 to 2 stools per day and are yellow in color and thick like peanut butter. If they suddenly increase in frequency and become loose, watery and sometimes contain mucus or blood you may have diarrhea.

Diarrhea in breastfed babies can be concerning for parents, but it’s important to remember that it’s a common issue and usually not a cause for alarm.

It is important to stay hydrated so offer them sips of cooled boiled water between breastfeeding.


causes of diarhhea


Diarrhea is usually not a big deal for infants, but it should be monitored to ensure that the baby does not get dehydrated. During periods of diarrhea, breast milk contains antibodies that help the baby fight infection and recover sooner. Breastfeed as normal, and offer oral rehydration fluids between breastfeeds to keep the baby hydrated.

It is important to note the color, frequency, and consistency of the stool. A change in this can indicate a problem such as food intolerance or an allergy to dairy products. If the baby is under 3 months old and has diarrhea, or the stool includes blood, mucus, pus, or continuous vomiting, contact the child’s pediatrician. Babies can also suffer from lactose intolerance, which happens when the body cannot digest the natural sugar found in milk (source: NHS). It is recommended that breastfeeding mothers eliminate dairy products from their diet until their baby is old enough to be weaned. This will help the mother to determine if she has an intolerance to one or more dairy proteins. The underlying cause of the intolerance can then be addressed by the doctor.

Food Sensitivity

Although breast milk has no germs, some babies have a mild reaction to proteins contained in formula or other foods they eat. These reactions are sometimes called food sensitivities or non-allergic food hypersensitivities.

The body’s response to these reactions is to ‘flush out’ the germs with watery or runny stools (diarrhea). This is to protect your baby from harmful germs and prevent them from getting into her system and causing sickness or infection.

Normal stools for a breastfed baby are often loose, seedy, or yellow and can even be a light green colour due to bile. If a baby has very watery, frequent, or persistent diarrhea it should be checked out by your Clinician/Health care worker.

Often a diet change is required to help treat diarrhea caused by a food allergy/sensitivity. Your Clinician/Health care worker may recommend removing specific foods on a trial basis to help find out which ones are the problem. This is known as an elimination–reintroduction diet. These diets are usually divided into different types depending on which body system is affected.

Changes in Diet

Newborn babies who are exclusively breastfed often have loose, watery stools. These are usually light yellow in colour and have a peanut butter-like texture. They might pass a stool up to 12 times per day. If their stools become runny, mucus-streaked, or more frequent than normal this is likely diarrhoea.

If your baby is introduced to solid foods for the first time it can upset their digestive system and result in diarrhea. They might also experience other symptoms such as vomiting or a fever. If this is the case, a doctor will probably advise you to keep them hydrated by offering fluids such as fruit juice or infant milk formula and monitor their condition closely for signs of dehydration.

Sometimes medications like antibiotics can leak into breast milk and cause the baby to have a bout of diarrhea. Similarly, some over-the-counter fever and pain relief for babies can be irritating to a breastfed baby’s tummy and cause them to have diarrhea.

Medical Conditions

Newborn babies, especially those who are exclusively breastfed, can have loose, watery stools several times a day. This is normal, even if the stools are yellow and seedy in consistency. However, if the stools are more frequent and looser than usual and have a mucus-streaked or unusually smelly appearance it could be baby diarrhea.

In most cases, it isn’t necessary to call the doctor if your child has these symptoms. However, if your baby’s bowel movements are bloody or they have a high fever, then you should call their healthcare provider immediately.

Diarrhea is most often caused by a stomach bug, but it can also be a sign of food poisoning, an allergy or intolerance to milk or another food, or a serious illness such as sickle cell disease or HIV. Rarely, a baby can develop diarrhea because their digestive system cannot digest certain proteins (like lactose) found in the formula they are eating, such as formula or dairy foods. In this case, their symptoms will likely last longer than usual and may not clear up on their own.


Many parents believe that a baby’s diarrhoea is caused by teething. This belief leads to some children being mistreated. A teething baby can get dehydrated very quickly and needs to be treated appropriately. Primary care professionals should be aware of this misconception and should encourage mothers to seek medical help for their babies if they have persistent diarrhea.

It is normal for babies to pass a stool with every breastfeeding session. These stools are light yellow to tan and often have small pieces that look like seeds. Breastfed babies can have up to 6 bowel movements a day. They may also have runny stools or a water ring around the edge of their stool.

If a baby is displaying symptoms of diarrhea, such as a fever, they need to see a doctor immediately. They can be given a rehydration solution. They should also be offered extra breast milk to prevent dehydration. Babies who are bottle fed can be given cooled boiled water. It is important that they are not given fizzy drinks or fruit juice as these can make their diarrhoea worse.


Breastfed babies can develop diarrhea due to several factors. Infections, such as viral or bacterial gastroenteritis, can lead to loose stools. A breastfeeding mother’s diet, particularly if it includes certain foods or beverages that irritate the baby’s digestive system, may also contribute. Furthermore, an oversupply of lactose-rich foremilk can cause watery stools. If a breastfeeding baby experiences persistent or severe diarrhea, it’s essential to consult a healthcare professional to identify the underlying cause and ensure the baby stays well-hydrated and healthy.

Q1: Can breast milk itself cause diarrhea in a breastfed baby?

A1: Breast milk is generally well-tolerated, but in some cases, an oversupply of foremilk, which is lower in fat, can lead to temporary watery stools resembling diarrhea.

Q2: What are common causes of diarrhea in breastfed infants?

A2: Diarrhea in breastfed babies is often caused by infections, such as viruses or bacteria, maternal dietary factors, or medications transferred through breast milk.

Q3: Should I be concerned if my breastfed baby has diarrhea?

A3: Mild diarrhea is usually not a cause for concern. However, if it persists, is severe, or accompanied by other symptoms like dehydration, high fever, or blood in stools, consult a healthcare provider.

Q4: How can I help my breastfed baby with diarrhea?

A4: Ensure your baby stays hydrated with frequent breastfeeding, and consult a pediatrician for guidance. If the diarrhea is due to maternal diet, consider dietary adjustments under medical supervision.

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