Hydration (Includes vomiting & diarrhea)

Many children lose fluids when they're sick. They drink less, evaporate more (such as fever or rapid breathing), or may have vomiting or diarrhea. This page will give you tips on hydrating children properly, review a few specific causes, and let you know when they need to be evaluated.

Signs of dehydration: (in rough order of severity, from mild to most severe, though there is considerable overlap)

  • Dry lips
  • Dry, tacky mouth
  • Concentrated urine
  • Headache
  • Rapid heart beat
  • Lack of tears with crying
  • Sunken eyes
  • Weight loss
  • Falling urine output to less than every 8 hours.

One note of caution: In rare cases, dehydration can be caused by peeing too much. So if your child is urinating an excessive amount but still shows all the other signs of dehydration, they need immediate evaluation.

Most dehydrated children can be effectively managed at home by using the best rehydration techniques, explained here, and lots of patience. However, if your child is severely dehydrated (urine output less than every 8 hours) or appears very ill (won’t respond to you, won’t stop screaming, appears in distress, etc), do not attempt this at home, take your child in to the Emergency Department. [If you’re at the 8 hour mark but your child is now looking great and really turning around (i.e. finally starting to drink a lot), give them 1-2 hours with close observation to see if they pee, but don't push things in an unwell child.]


Before you start the rehydration process, if at all possible, weigh your child. This will help us monitor progress. If you have an infant and nothing but an adult scale, you can weigh yourself with and without your infant, then take the difference between the weights. Not 100% accurate, but better than nothing.

How do I rehydrate my child?

Slow and steady wins the race. Rather than go for large amounts quickly, go for small amounts frequently. Large amounts distend the sensitive stomach and cause vomiting, but small amounts sneak through and are absorbed faster.

Using an electrolyte solution. When a lot of vomiting is present, or if the child is not eating food, you'll need to hydrate with an electrolyte solution. This is a combination of salt, sugar and water that is actually absorbed faster than plain water, and replenishes the electrolytes they may have lost.

Always give yourself a fluid goal - you're more likely to meet it if you set it. A good goal to start with is 3 ounces for every ten pounds of body weight. So a 20 pound child should get 6 ounces, and a 50 pound child should get 15 ounces. Set that amount aside so you can use it as a gauge for your progress. 

Start with 1 teaspoon and then wait 10 minutes. Do that a few times, then up it to every 5 minutes. If still doing well, increase to 2 teaspoons every 5 minutes, which is a rate of about 4 ounces per hour. Depending on your child's size, you might increase this amount further as appropriate (3-4 teaspoons at a time), so you can finish the total amount within 1-2 hours max.

How to administer: if you have a medicine syringe, those work great to keep the pace under control. If not, you can use a spoon or allow them to take one small sip at a time. Tip: breastfed babies may do better if you pump and bottle/syringe-feed so you can control the amount they’re getting.

How about food? For older children and infants who are eating solid foods, bland solid foods are OK in small amounts if your child can tolerate them without vomiting. But always prioritize fluids over food if you have to pick between one and the other. Good choices include broth or soup (i.e. good old chicken noodle soup), bananas, whole grain crackers, etc. Avoid dairy products and junk food, which can irritate the stomach and gut.

Is juice OK? If your child has diarrhea, try to limit sweet drinks such as juice, Gatorade, and soda, which can make diarrhea worse. If there's no diarrhea, a little juice is OK, but too much will create diarrhea, and you start to lose fluid again. Electrolyte solution is safer, has less sugar and won't cause diarrhea.

Is Dairy OK? Some children will tolerate dairy during these illnesses, but many can develop a temporary lactose intolerance. To play it safe, you probably want to avoid dairy as long as you can get them to take something else. However, if dairy is all they will take, AND they tolerate it well, it is better than nothing.

Alternate your liquids and get creative so they don’t get tired of the same old drink. Try popsicles, or crushed ice. You can even make popsicles out of your electrolyte solution or buy them pre-made (Pedialyte®popsicles)

If your child refuses to take the fluids: While of course convincing them to do so voluntarily is preferred, it is OK to force the fluids into their mouth if they refuse, just as you would a teaspoon of medicine they don't want to take. This can be a highly effective, albeit difficult, strategy to avoid the ER. In such cases it's kind of up to you if you prefer the forced oral hydration or take them in for the forced IV, often at that point it's a rock or a hard place. One way or another, express to them compassionately that this medicine is not negotiable, they can't choose not to drink it. Tip: if they have a high fever, sometimes bringing the fever down will convince them to start drinking, as well as lessen fluid losses. Worth trying...

How do I maintain hydration?

Once hydrated, try to stay ahead. Frequent sips throughout the day is the way to go, most kids aren't drinking frequently enough. If you fall behind, or it only got you half-way there, repeat the process above after a short break.

Have liquidy meals like soups. Try to avoid really dry foods.

A humidifier can help if your child has a respiratory issue, because they may evaporate less fluid from their lungs that way.

Manage fever. While we normally don't like to artificially bring down a child's fever, if it is a high fever and they're unable to hydrate, a dose of fever reducers can work wonders for hydration.

A few points worth mentioning

Diarrhea can last a long time, even up to two weeks! It is perfectly fine for this to happen as long as your child remains well hydrated and well appearing. Vomiting may be present at the beginning as well, and usually subsides after 3-5 days. It is normal for diarrhea and vomiting to go back and forth, especially as you work on re-introducing foods, so take it slow.

Call if: blood in the stool, more than 3-4 days of fever at the beginning, diarrhea lasts more than 2 weeks 

Tip: if you can’t tell how often your infant/toddler is urinating due to mixing with stool in the diaper, put a bunched up tissue over the vagina or penis to try and absorb the urine and keep it separate from the diarrhea.

Vomiting without diarrhea can be due to many different things, and sometimes this can be serious. Usually diarrhea is just a day behind, so as long as your child does not look very ill it is OK to wait a day or two to see what develops. I am more concerned about vomiting in the presence of fever, heavy cough, respiratory difficulty, abdominal pain, or very young infants (less than 3 months). If these are present, please come see me as soon as possible, and call right away or take them to the Emergency Room after hours if they appear urgently sick.

Sore throat can cause dehydration in children because the throat pain makes it hard for them to drink. To reduce the pain, try soothing liquids, ice cream, popsicles, lozenges, or warm water with honey (not to be given to infants less than 12 months, of course). You can also try acetaminophen or ibuprofen. Then encourage them to increase their oral intake despite their discomfort as much as possible.

When to take your child in to the ER:

  • Your child is getting rapidly dehydrated and starting to look really ill despite your attempts to rehydrate.
  • Your child’s urine output drops to less than every 8 hours and shows no sign of turning the corner in the near future.
  • Your child is becoming unresponsive
  • Your child has signs concerning for other illness, such as shortness of breath, severe abdominal pain, severe cough with vomiting, etc.

Same-day appointments

For urgent needs, same-day appointments are available Monday through Friday. Please call as early in the day as possible, the more notice we have the easier it is to fit everyone in. 

Need help outside of office hours?

Firstly, if your child has an emergency, please call 911 or go directly to the ER - they will contact us if needed once your child has been evaluated.

Urgent Care centers can also be helpful when something needs to be seen outside of office hours but it's not an emergency. 

For our list of preferred Urgent Cares and ERs, see our resources page.

And if you have something that might need urgent attention but you're not sure/don't know what to do, we can help: