Baby diarrhea is often caused by infections from viruses, bacteria, parasites or fungi, and happens when a baby has at least 3 bowel movements with loose or watery stool within a 24-hour period.

It’s possible to tell if a baby has diarrhea by checking the diaper for stool that is more liquid than usual, has a different color or gives off a strong smell, similar to rotten eggs. It’s also important to check for the presence of blood or mucus in the stool, changes in breathing or cold hands and feet, as these may be signs of a more serious situation.

To treat baby diarrhea, it’s important to see a pediatrician and continue breastfeeding or infant formula. If the baby is over 6 months old, complementary foods should also be maintained to prevent malnutrition and dehydration. The pediatrician may prescribe oral rehydration solution, antibiotics and/or probiotic supplements to treat the infection and restore the baby's gut flora.

How to know if a baby has diarrhea

There are a few signs to look out for to determine if a baby has diarrhea:

3 or more watery bowel movements per day
A color that is different from usual
A strong or foul odor, especially when caused by gastroenteritis
Stool that leaks out of the diaper and stains the baby's clothes

The baby may also seem more irritable than normal, may refuse to eat or breastfeed, and may have other symptoms like fever, stomach pain or vomiting. Signs of dehydration can also appear, such as dry mouth and lips, irritability or fewer tears when crying.

What causes diarrhea in babies

When diarrhea lasts up to 14 days, it is often caused by spoiled food or infections from parasites, viruses or bacteria, commonly known as gastroenteritis.

When diarrhea lasts for more than 14 days, the most common causes are lactose intolerance, gluten intolerance or allergy, the use of antibiotics or intestinal diseases like irritable bowel syndrome or inflammatory bowel disease.

Can it be COVID-19?

Although COVID-19 infections are less common in babies, it has been observed that children may present with symptoms similar to a viral illness, including diarrhea. Therefore, if the baby has diarrhea along with symptoms like fever, vomiting or reduced appetite, it’s important to see a pediatrician for proper evaluation.

How to treat baby diarrhea

Parents or caregivers should take the baby to a pediatrician to determine the cause of diarrhea and start the appropriate treatment. However, some care measures can be taken at home, especially related to feeding, to help prevent dehydration, weight loss and vitamin or mineral deficiencies.

1. Feeding a baby with diarrhea

To treat a baby with diarrhea, it’s important to maintain the baby’s regular feeding routine. For babies under 6 months who are exclusively breastfed, breastfeeding should continue on demand. For babies who are not breastfed, infant formula and water should be maintained.

For babies 6 months and older, breastfeeding on demand or formula feeding should continue, and solid food should be maintained with fresh fruit purees, vegetables, cereals, legumes and proteins.

During diarrhea episodes, it’s common for babies to lose their appetite. Therefore, it’s recommended to offer food in smaller portions, more frequently throughout the day, according to the baby’s hunger.

Oral rehydration solution may also be necessary, as diarrhea leads to significant fluid loss through stool, increasing the risk of dehydration. The Brazilian Society of Pediatrics recommends the following amounts of rehydration solution:

For babies under 1 year: 50 to 100 mL after each episode of diarrhea
For babies between 1 and 2 years: 100 to 200 mL after each episode

2. Medications for baby diarrhea

After assessing the cause of diarrhea, the pediatrician may prescribe medications like pain relievers to reduce discomfort or fever, if present. Antibiotics may be needed if the diarrhea is caused by a bacterial infection.

Probiotic supplements may also be recommended. These contain beneficial bacteria that help restore the balance of the gut microbiota and promote faster recovery.

When to see a doctor

Parents or caregivers should take the baby to the doctor if the baby presents with any of the following symptoms:

More than 3 episodes of diarrhea in a day
Low energy levels or excessive sleepiness during the day
Severe diarrhea with no improvement after 2 days
Mucus or blood in the stool
Excessive thirst or reduced urine output
Refusal to eat or drink
Changes in breathing or heart rate
Cold hands and feet
Other symptoms like vomiting or a fever over 100.4°F (38°C)

Although viruses commonly cause vomiting, diarrhea and fever in babies, these symptoms can also be related to food intolerances or allergies.