Diarrhea and vomiting (stomach flu or “gastro”)

Each child is unique, with their own particular bowel movement patterns. The frequency, quantity, consistency, and colour of their stools vary. For example, a baby may have up to 10 bowel movements per day in the first weeks of life and much fewer afterwards.

Some babies have very soft, even liquid, stools. Breastfed babies’ stools are often yellow or green. Babies fed commercial formula will tend to have greenish beige stools (see Stools).

Some babies spit up a lot more than others. So it’s important to get to know your baby and what is normal for her.

You should worry only if her habits change, if she’s drinking or eating less, losing weight, or seems ill. If her stools are softer than usual, but not more frequent or abundant, and if she doesn’t seem ill, it’s probably not stomach flu (gastroenteritis). Keep an eye on her to see if the situation resolves itself within a few days. Consult Info-Santé (8-1-1) or a doctor if the situation persists.

If you think she might have COVID-19, contact Info-Santé (8-1-1) or call a doctor.

Gastroenteritis (stomach flu or ”gastro”)

Gastroenteritis is a very common infection in children. Almost all children come down with it at least once in their first year.

A child with gastroenteritis is clearly ill:

  • She feels sick, is irritable, and eats and plays less.
  • She has diarrhea: her stools are liquid (almost like water) and are more frequent and abundant than normal.
  • She may also vomit (more abundantly and violently than usual).
  • She may have a fever.

Information to which you should pay special attentionDon’t give your child any anti-nausea or anti‑diarrhea medication without your doctor’s advice. This type of medication can have serious side effects and is rarely recommended for young children.

Gastroenteritis germs are easily spread from one person to another, especially from one child to another. To prevent spreading the infection, it’s important to wash your hands regularly, especially after handling dirty diapers, stools, or vomit, and before handling food.

What to do?

Most cases of gastroenteritis are caused by a virus and disappear on their own within a few hours or days. A calm environment and plenty of liquids can help your child feel better. The most important thing is to regularly offer her something to drink to prevent dehydration.


Dehydration can occur when your child doesn’t get enough water and minerals from her food to replace those lost due to diarrhea and vomiting. When your child has gastroenteritis, it’s important to check for the following signs of dehydration:

  • Dry mouth
  • Lack of tears
  • Increased thirst
  • Less urine than usual
  • Drowsiness or irritability

Preventing dehydration

If your baby is a bit fretful but otherwise seems ok, if her eyes and mouth are moist, and she wets her diaper regularly, she’s probably not dehydrated. Keep giving her the usual amount of milk and offer her a drink more often than usual if she’ll take it. A normal diet will help reduce the diarrhea.

If your child vomits or refuses to eat, keep giving her her usual milk. If she’s started eating solid food, offer her foods that she particularly likes and is able to keep down, then gradually reintroduce her normal diet when she feels better, ideally within 4 to 12 hours. Avoid giving her juice, even if it’s diluted, or soft drinks, even if they’re flat, because they’re too sweet and can sometimes even make the diarrhea worse.

Preventing dehydration during gastroenteritis

Breastfed baby Baby fed commercial infant formula or 3.25% milk

Keep breastfeeding. If your baby only takes a little milk at a time, breastfeed more often.

If she refuses to breastfeed, give her small quantities of expressed breast milk using a sippy cup, spoon, dropper, or straw.

Offer her her usual formula or 3.25% milk more often and in smaller quantities.

If she isn’t taking her bottle well, use a sippy cup, spoon, dropper, or straw.

Regardless of the type of milk, if your baby has started eating food

Offer her food she particularly likes and can keep down. Avoid juice and soft drinks.

Dehydrated baby

One or more of the following signs indicate that your baby is somewhat dehydrated:

  • Her mouth and tongue are a little drier than usual.
  • She seems to be thirstier than usual.
  • She is peeing a little less than usual.

One or more of these signs indicate that you need to start rehydrating her. You should frequently offer her small quantities of fluid. Breast milk or oral rehydration solutions (ORS) are the best choice, depending on the case.

Just as you would do to prevent dehydration, avoid giving her juice, even if it’s diluted, or soft drinks, even if they’re flat, or sports drinks like Gatorade™ because they’re too sweet and can sometimes even make the diarrhea worse. If the diarrhea is abundant, avoid giving only water because it doesn’t contain enough sugar and salt, which your baby needs to rehydrate.

Your child will probably not feel like eating if she has vomited a lot and is dehydrated. Keep her on a liquid diet and gradually phase in solid food when she feels a little better and has stopped vomiting.

Treating dehydration

Breastfed baby Baby fed commercial infant formula or 3.25% milk

Keep breastfeeding.
Breastfeed more often, for shorter periods at a time.
If she has difficulty nursing, give her small quantities of expressed breast milk using a sippy cup, spoon, dropper, or straw.
If your baby vomits breast milk, offer her ORS, according to the instructions in the column on the right.

Stop giving her her usual formula or 3.25% milk for about 4 hours.
Instead, give her small quantities of ORS in a bottle, sippy cup, spoon, dropper, or straw.
ORS in the form of ice pops can be given to children 1 year and older.

Regardless of the type of milk, if your baby has started eating food

Keep her on a liquid diet, for only a few hours.
If your baby vomits, gradually start reintroducing her usual food when the vomiting becomes less frequent. After 24 to 48 hours, most children are able to return to their normal diet.

It is particularly important to keep giving your baby regular fluids, according to what she can keep down. If the vomiting persists, give her small quantities of liquid, more often. For example, you can give her 5 to 15 ml (1 tsp. to 1 tbsp.) of breast milk or oral rehydration solution every 5 to 15 minutes. Once your baby is feeling a little better, gradually increase the quantities, so long as she can keep her food down.

Oral rehydration solutions (ORS)

Oral rehydration solutions (ORS) contain precise ratios of water, salt, and sugar to replace what has been lost through diarrhea and vomiting.

You can buy ready-made ORS in drugstores, in various flavours of ready-to-serve drinks, ice pops, and packets of powder. Your pharmacist can help you choose the right product.

The Canadian Paediatric Society suggests that parents always keep ORS on hand. The powdered form, which you dissolve in cooled boiled water, is less expensive and more practical when you’re away from home, but you run the risk of making a measuring mistake when diluting it. The Canadian Paediatric Society therefore prefers pre-prepared ORS.

Encourage your child to drink as much of this solution as she can, using a bottle, sippy cup, spoon, dropper, or straw. She may prefer it cold or in the form of an ice pop if she’s over 1 year old.

The Canadian Paediatric Society does not recommend using homemade ORS because mistakes can be made in preparing them. However, if you can’t get hold of a store-bought ORS (late at night, for example), you can make a homemade, emergency ORS yourself using the following recipe.

Mix together the following ingredients:

  • Ready-to-serve orange juice without added sugar: 360 ml (12 oz.)
  • Cooled boiled water: 600 ml (20 oz.)
  • Salt: 2.5 ml (½ level tsp.), never more

Follow this recipe carefully. Measure out the exact quantities, using a measuring spoon and measuring cup. Improper solution preparation can actually worsen dehydration.

Only use a homemade ORS as a last resort (while you’re waiting for the drugstore to open, for example) and never for more than 12 hours.

Information to which you should pay special attentionConsult a doctor right away if your child is showing the following signs:

  • She is very irritable and constantly cries.
  • She shows signs of severe dehydration (she’s very drowsy, wets less than 4 diapers in 24 hours, cries without tears, has a dry, pasty mouth and tongue, and sunken eyes).
  • She vomits often for a period of more than 4 to 6 hours.
  • There is blood in her stools.

When to consult a health professionnal?

Gastroenteritis symptoms usually lessen over the course of a few days. If the diarrhea continues for more than 1 or 2 weeks, consult your doctor.

If you think your child might have COVID-19, contact Info-Santé (8-1-1) or call a doctor.