It often starts suddenly: a child who was fine at dinner wakes up vomiting, and by morning there is diarrhea too. Stomach bugs spread quickly through families, schools and child care centers, especially in the colder months. Most children recover in a few days without medicine. The most important job for parents is preventing dehydration, which happens when a child loses more fluid than they take in. This guide explains how to rehydrate your child step by step, what to watch for and when to call the doctor.
What Is a "Stomach Bug"?
Most stomach bugs are viral gastroenteritis, an infection of the stomach and intestines. Norovirus is the most common cause in the United States, and rotavirus can cause severe illness in babies and young children who aren't vaccinated. Bacteria and parasites from contaminated food or water can also cause similar symptoms.
Despite the nickname "stomach flu," gastroenteritis is not caused by the influenza virus, and the yearly flu shot does not prevent it.
Common Symptoms
- Nausea and vomiting, often in the first 24 hours
- Watery diarrhea, which can last several days
- Stomach cramps
- Low-grade fever, headache and body aches
- Decreased appetite and tiredness
Vomiting usually stops within a day or two. Diarrhea may continue for up to a week and slowly improve.
Signs of Dehydration
Babies and young children can become dehydrated faster than older children and adults. Watch for:
- Fewer wet diapers or less urine: for example, no wet diaper in 6 hours for an infant, or no urine in 8 hours for an older child, or dark yellow urine
- Dry or sticky mouth and lips
- Few or no tears when crying
- Sunken eyes, or a sunken soft spot on top of a baby's head
- Unusual sleepiness, weakness, fussiness or irritability
- Cool, pale or blotchy skin, or fast breathing
How to Rehydrate Your Child, Step by Step
Use an oral rehydration solution
Oral rehydration solutions (ORS), sold in pharmacies and grocery stores as liquids or ice pops, contain the right balance of water, salts and sugar to replace what is lost through vomiting and diarrhea. They work better than water alone, juice, soda or sports drinks. Sugary drinks can make diarrhea worse, and plain water does not replace lost salts.
Start small and go slow
After your child vomits, give the stomach a short rest (about 15 to 30 minutes), then:
- Give about 1 teaspoon (5 mL) of ORS every few minutes using a spoon, syringe or medicine cup.
- If your child keeps it down for about an hour, slowly increase the amount.
- If your child vomits again, rest for 15 to 30 minutes and start over with small sips.
- Continue to replace fluids lost with each episode of diarrhea or vomiting.
Small, frequent sips are much more likely to stay down than a large drink all at once, even if your child is very thirsty.
Feeding babies
If you are breastfeeding, keep nursing, offering shorter, more frequent feeds. For formula-fed babies, your pediatrician may suggest a short period of ORS followed by a return to regular formula. Don't dilute formula. Babies younger than 6 months should not be given plain water.
What to Eat When Your Child Feels Better
Once vomiting has stopped and your child is hungry, return to a normal, age-appropriate diet. There's no need to stick strictly to bland foods for days. Good choices include rice, bread, crackers, potatoes, bananas, yogurt, lean meats, cooked vegetables and soups. Avoid very greasy or sugary foods and large amounts of juice until diarrhea improves. It's normal for appetite to be low for a few days, as long as your child is drinking well.
Medicines: What Helps and What to Avoid
- Don't give anti-diarrhea medicines to children unless your pediatrician recommends them. Bismuth subsalicylate products contain a salicylate (related to aspirin) and are not recommended for children.
- Antibiotics don't help viral stomach bugs.
- Fever or pain relievers such as acetaminophen, or ibuprofen for children 6 months and older, can be used for comfort. Ask us before giving medicines to a child who is vomiting.
- Your pediatrician may sometimes prescribe a medicine to reduce vomiting in certain children so they can drink.
When to Get Medical Help
Call 911 or go to the emergency department if your child is very sleepy, limp or hard to wake, is breathing fast, has signs of severe dehydration, or has severe, constant belly pain.
Contact your pediatrician promptly if your child:
- Is younger than 3 months and is vomiting or has diarrhea or fever
- Shows any signs of dehydration, or can't keep down even small sips for several hours
- Has blood in the vomit or stool, or vomit that is green or yellow-green
- Has belly pain that is severe or settles in one spot, especially the lower right side
- Has vomiting lasting more than 24 hours or diarrhea lasting more than a few days without improving
- Has a high fever, a stiff neck, or vomiting after a head injury
- Has a chronic medical condition such as diabetes
How to Stop the Spread at Home
- Wash hands with soap and water for at least 20 seconds after using the bathroom, changing diapers and cleaning up, and before preparing food. Alcohol-based hand sanitizers don't work as well against norovirus.
- Clean contaminated surfaces with a bleach-based household cleaner, following label directions.
- Wash soiled laundry right away on the longest cycle and dry completely.
- Don't let a sick person prepare food for others while sick and for a couple of days after recovery.
- Keep children home from school or child care until symptoms have stopped; many programs ask that children stay home until at least 24 hours after the last episode of vomiting or diarrhea.
Prevention: The Rotavirus Vaccine
Rotavirus vaccine is given by mouth in the first months of life and protects babies from one of the most severe forms of gastroenteritis. It is part of the routine schedule recommended by the American Academy of Pediatrics. Learn more on our immunizations page.
The Bottom Line
Most stomach bugs pass within a few days. Your main focus is keeping your child hydrated with small, frequent sips of an oral rehydration solution and watching closely for signs of dehydration. Keep a few ORS packets or bottles in your medicine cabinet before you need them, and add them to your travel health kit. If you are ever worried, contact us. For related topics, see signs of appendicitis and when to take your child to urgent care.
This article is general health information for parents and is not a substitute for medical advice. If you are worried about your child, contact your pediatrician; in an emergency, call 911.
Questions about your child's health?
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