When a child vomits or has diarrhea, she may become dehydrated. Dehydration occurs when your child doesn’t get enough water and minerals from what she eats and drinks to replace those lost due to diarrhea and vomiting.

If your child vomits or has diarrhea but does not show any of the symptoms described in the chart below, be sure to take steps to prevent dehydration.

Preventing dehydration

What to do?

Essential information to remember

To prevent dehydration in your child, have her drink more often than usual.

If your child hasn’t started eating solid food, keep giving her the usual amount of milk, and offer to feed her more often than usual. If she has difficulty nursing or isn’t taking her bottle well, use a sippy cup, spoon, dropper, or straw.

If she has started eating solid food, offer her food that she particularly likes and is able to keep down. Also have her drink more often than usual.

If your child has heavy diarrhea or vomiting and refuses to drink or eat, you can give her small amounts of oral rehydration solution. For example, you can give her 5 to 15 ml (1 tsp to 1 tablespoon) of oral rehydration solution every 5 to 15 minutes (see Oral rehydration solutions (ORS) below).

Watch for the signs of dehydration described on page 668. An Info-Santé nurse (8-1-1) can advise you at any time.

Dehydrated baby

Certain signs indicate if your child is dehydrated. The following table lists the signs of mild and moderate to severe dehydration, and what to do if your child is dehydrated.

Mild dehydration

Signs of dehydration

  • Mouth and tongue slightly drier than usual
  • Increased thirst
  • Fewer wet diapers than usual

What to do?

First, call Info Santé (8-1-1) or a doctor to assess the situation.

You can start dehydration treatment at home (see below Treatment of mild dehydration).

Moderate to severe dehydration

Signs of dehydration

  • Lack of tears when child cries
  • Drowsiness or irritability
  • Sunken eyes
  • Less than 4 diapers wet in 24 hours

What to do?

See a doctor or take your child to the emergency room right away.

Treatment of mild dehydration

To treat mild dehydration, you should give your child small quantities of liquid very often. Breast milk or oral rehydration solutions (ORS) are the best choices (see Oral rehydration solutions (ORS) below).

Babies who have not started eating solid food

Breastfed baby

Breastfeed more often, for shorter periods at a time. If your baby has difficulty nursing, give her small quantities of expressed breast milk using a sippy cup, spoon, dropper, or straw. Between feedings, give her small quantities of oral rehydration solution (ORS).

Continue breastfeeding and giving your child ORS, even if she throws up her milk. You can increase the quantity of ORS if it is well tolerated. If vomiting persists, see Vomiting.

Baby fed commercial infant formula

Stop giving her commercial infant formula for around 4 hours. Give her small quantities of oral rehydration solution (ORS) in a bottle, sippy cup, spoon, dropper, or straw.

Return to her usual preparation after 3 to 4 hours.

Babies who eat solid food

If your child vomits, stop feeding for about 4 hours. Give her small amounts of oral rehydration solution (ORS) regularly, using a spoon.

Gradually start reintroducing her usual food when the vomiting becomes less frequent. After 24 to 48 hours (1 to 2 days), most children are able to return to their normal diet.

For example, you can offer 5 to 15 ml (1 teaspoon to 1 tablespoon) of breast milk or oral rehydration solution every 5 to 15 minutes. Once your baby is feeling a little better, gradually increase the quantities, according to her tolerance.

Avoid giving her juice, soft drinks (even flat), sports drinks, or rice water. If your baby has diarrhea or severe vomiting, avoid giving her only water as well. None of these drinks contain the right quantities of sugar and salt your child needs to rehydrate.

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 find ORS in various flavours and forms at the drug store:

  • Ready-to-serve
  • Packets of powder
  • Ice pops

Your pharmacist can help you choose the right product and use it as directed. The Canadian Paediatric Society suggests that parents always keep ORS on hand.