The most common reason your daughter is throwing up is a stomach virus, often called the “stomach flu.” Viral gastroenteritis accounts for the majority of vomiting episodes in children of all ages, and symptoms typically last one to two days, though they can occasionally stretch to two weeks. While a stomach bug is the most likely explanation, several other causes are worth knowing about, because the right response depends on what’s behind the vomiting.
Stomach Viruses: The Most Likely Cause
Norovirus is the most common cause of foodborne gastroenteritis worldwide and affects both children and adults. Rotavirus is the leading cause of viral gastroenteritis specifically in young children, who typically pick it up by touching contaminated surfaces and then putting their fingers in their mouths. Both viruses spread fast through households and daycare settings.
A stomach virus usually comes with diarrhea and sometimes a low fever. Your daughter may have been around someone with similar symptoms in the past day or two. The vomiting tends to be the worst in the first 12 to 24 hours and then gradually tapers off. Diarrhea often lingers a bit longer than the vomiting itself.
Other Common Causes by Age
If your daughter is an infant, gastroesophageal reflux is the second most common cause of vomiting. Babies with reflux tend to be fussy during or after feedings and may arch their backs. A less common but important cause in babies between 2 and 12 weeks old is pyloric stenosis, where the muscle at the bottom of the stomach thickens and blocks food from passing through. The hallmark is forceful, projectile vomiting right after feeding.
In older children and adolescents, bacterial infections become more common. These tend to cause bloody diarrhea, fever, and crampy belly pain alongside the vomiting. Ear infections, strep throat, and urinary tract infections can also trigger vomiting in kids, even when the stomach itself isn’t the problem. If your daughter has ear pain, a sore throat, or pain with urination, the vomiting may be a side effect of one of these infections rather than a stomach bug.
Food Reactions That Cause Vomiting
Some children have a condition called food protein-induced enterocolitis syndrome, or FPIES. Unlike a typical food allergy with hives or swelling, FPIES causes repetitive vomiting one to four hours after eating a trigger food. Children with it can also become unusually sleepy or limp after a reaction. Common triggers include cow’s milk, oats, poultry, egg, peanuts, and cashews. If you notice a pattern where your daughter vomits hours after eating a specific food but seems fine otherwise between episodes, FPIES is worth discussing with her pediatrician.
Cyclic Vomiting Syndrome
If your daughter has repeated episodes of intense vomiting that seem to come out of nowhere, resolve completely, and then return weeks or months later in a predictable pattern, she may have cyclic vomiting syndrome. Episodes often start in the middle of the night or early morning, between 2 a.m. and 7 a.m., and can last anywhere from a few hours to several days. The key feature is the “on-off” pattern: she’s completely fine between episodes, then suddenly hit with severe nausea and vomiting again. One study of 181 children found episodes recurred on average every 1.8 months, though the range varied widely from every few weeks to once a year.
Signs That Need Immediate Attention
Most vomiting in children resolves on its own, but certain red flags point to something more serious. Intussusception, a condition where one part of the intestine slides into another, causes sudden episodes of severe belly pain roughly every 15 to 20 minutes. A baby with intussusception will pull their knees to their chest and cry loudly during these waves of pain. Stool that looks like currant jelly (a mix of blood and mucus) is a hallmark sign and requires emergency care.
Appendicitis typically causes pain that starts around the belly button and moves to the lower right side, along with vomiting, fever, and a loss of appetite. If your daughter’s belly is tender to the touch and the pain gets steadily worse, get her evaluated quickly.
If your daughter hit her head before the vomiting started, that changes things entirely. Vomiting right after a head injury, or repeated vomiting in the hours following one, is a danger sign listed by the CDC for children of all ages. Go to the emergency department if vomiting follows a bump, blow, or jolt to the head.
Diabetic ketoacidosis, though uncommon, can also cause vomiting in children. Warning signs include a fruity smell on her breath, excessive thirst, frequent urination (or new bedwetting), unexplained weight loss, and confusion or drowsiness. This is a medical emergency.
How to Keep Her Hydrated
Dehydration is the biggest practical risk when a child is vomiting. The key is to offer small amounts of fluid frequently rather than large drinks, which are more likely to come back up. Start with about 5 milliliters (one teaspoon) every one to two minutes. A syringe or medicine dropper works well for younger children. Gradually increase the amount as she keeps it down. Even children who are actively vomiting can be successfully rehydrated this way more than 90% of the time.
Oral rehydration solutions (sold as Pedialyte and similar brands) are ideal because they replace both fluids and electrolytes. For mild dehydration, aim for roughly 50 milliliters per kilogram of your daughter’s body weight over two to four hours. So for a 20-pound (9 kg) child, that’s about 15 ounces spread over several hours, given in tiny sips.
Watch for signs of dehydration: a dry or sticky mouth, no tears when crying, and reduced urination. For newborns through 4 months, fewer than six wet diapers in a day is concerning. For older babies and children, fewer than three wet diapers or bathroom trips in a day, or urine that’s very dark, signals dehydration that needs medical attention. Hard or fast breathing is another warning sign.
What to Feed Her After the Vomiting Stops
The old advice to stick with the BRAT diet (bananas, rice, applesauce, toast) is outdated. The American Academy of Pediatrics no longer recommends it because those foods are too low in fiber, protein, and fat to help the gut recover. Some pediatricians believe the BRAT diet can actually make symptoms last longer.
Instead, once your daughter can keep fluids down, move her back to a normal, balanced diet within about 24 hours of getting sick. Offer a mix of fruits, vegetables, meat, yogurt, and complex carbohydrates. Let her appetite guide the portions. She may eat less than usual for a few days, and that’s fine as long as she’s staying hydrated.