My Child is Vomiting and Has Diarrhea. What Should I Do?

Keep your child hydrated with small, frequent sips of fluid and watch closely for signs of dehydration. That is the single most important thing you can do when vomiting and diarrhea strike together. Most episodes of gastroenteritis in children are caused by viruses, resolve on their own within a few days, and need no medication at all. But dehydration can develop fast in small bodies, so knowing what to offer, how much, and when to escalate to medical care makes a real difference in how smoothly your child recovers.

Why Fluids Come First

When a child vomits or has watery stools, they lose both water and electrolytes like sodium and potassium. Young children have a higher ratio of body surface area to weight than adults, which means they lose proportionally more fluid in a shorter time. The goal during a stomach bug is not to stop the vomiting or diarrhea immediately but to replace what is being lost so the body can fight off the infection without tipping into dehydration.

Oral rehydration solutions are the standard tool. These are pre-mixed drinks (sold under names like Pedialyte, Dioralyte, or store-brand equivalents) designed to contain the right balance of sugar and salt to help the gut absorb water efficiently. Research across both high-income and low-income settings has confirmed that solutions containing the appropriate sodium concentration are safe and effective for treating children with acute gastroenteritis regardless of the cause.¹ You do not need a prescription for them; they are available in most pharmacies and grocery stores.

A practical starting guideline: children weighing under about 22 pounds (10 kg) should get roughly 60 to 120 mL of oral rehydration solution after each episode of vomiting or diarrheal stool, while children above that weight should get 120 to 240 mL per episode, on top of whatever they normally drink during the day.² These are ballpark numbers. The point is to keep offering fluid consistently, not to hit a precise target.

The Sip-by-Sip Approach

If your child is actively throwing up, do not hand them a full cup and hope for the best. The most effective strategy is small amounts at frequent intervals: a teaspoon or tablespoon every couple of minutes. Even if they vomit some of it back up, a portion usually stays down and gets absorbed. Waiting 15 to 30 minutes after a big vomiting episode and then restarting tiny sips tends to work better than waiting hours for the stomach to “settle” while the child gets increasingly dry.

For older toddlers and school-age children with mild symptoms, a trial published in JAMA found that half-strength apple juice followed by whatever fluids the child preferred actually worked better than a commercial electrolyte solution at preventing treatment failure. Children given the dilute juice and preferred fluids were less likely to need intravenous rehydration (about 2.5% versus 9%) compared with those given only the maintenance electrolyte drink.³ The takeaway is that for mild cases in children over about one year old, getting them to drink something they are willing to swallow matters more than insisting on a specific product. For moderate or severe dehydration, though, a proper oral rehydration solution is still the better choice because it replaces electrolytes more reliably.

How to Spot Dehydration

No single physical sign tells you with certainty that your child is dehydrated. Research on clinical dehydration assessment has found that individual signs like dry lips or decreased urine, taken alone, are not reliable enough to make the call. But a combination of signs is much more informative. A study evaluating the validity of common clinical markers found that when any two or more of four key signs were present, there was a strong indication of at least 5% fluid loss:⁴

• Capillary refill: press your child’s fingernail bed or the skin on their forehead for two seconds and release. If the color takes more than two seconds to return, that is a concerning sign.
• No tears: your child cries but produces no tears.
• Dry mouth: the inside of the mouth and tongue look parched rather than glistening.
• Ill appearance: the child looks generally unwell, listless, or unusually drowsy.

Other useful indicators studied alongside those four include sunken eyes, decreased skin turgor (when you gently pinch the skin on the back of the hand or abdomen and it stays “tented” instead of snapping back), and weak pulse.⁵ A parent reporting decreased urine output is sensitive but not very specific on its own, meaning it catches most dehydrated kids but also flags some who are fine. Still, noticeably fewer wet diapers or infrequent trips to the bathroom is worth paying attention to.

The practical rule: if you see two or more of those warning signs at the same time, your child needs medical evaluation. One sign alone warrants closer monitoring and more aggressive fluid pushing at home.

When to Get Medical Help

Some situations call for a phone call to your pediatrician, and some call for going straight to an emergency department. Here is a rough guide:

• Call your doctor: vomiting or diarrhea has lasted more than 24 hours without improvement, your child has a fever above 102°F (39°C) that is not coming down, they refuse all fluids, or you notice blood or mucus in the stool.
• Go to the emergency room: your child is lethargic or difficult to wake, has sunken eyes with no tears, has not urinated in six or more hours (or has had no wet diaper in four to six hours for an infant), has a sunken soft spot on the head (in babies), or shows signs of rapid breathing or a weak pulse.
• Infants under six months: the threshold for seeking care is lower. Babies this young dehydrate faster, and guidelines recommend starting oral rehydration early if there are more than eight watery stools in 24 hours or more than four vomiting episodes in 24 hours.⁶ If a very young infant is not tolerating breast milk or formula at all, they should be seen the same day.

If you are unsure whether to go in, telemedicine or a nurse triage line can be surprisingly useful. A study that tested virtual dehydration assessments found that clinicians could accurately identify children with no dehydration through video with a sensitivity of about 97%, meaning they caught nearly all the kids who were actually dry.⁷ A virtual check does not replace a hands-on exam for moderate or severe cases, but it can help you decide whether to head out or continue managing at home.

Medications That Help (and Those That Do Not)

Parents often want to give something to stop the vomiting. Most over-the-counter anti-nausea medications are not recommended for children, but ondansetron (brand name Zofran) is an exception that doctors may prescribe. A single dose has been shown in multiple trials to cut ongoing vomiting roughly in half within a few hours, cut the need for IV fluids by more than half, and reduce hospitalization rates during the acute period.⁸ In one emergency department trial, children who received ondansetron were far less likely to vomit (about 14% versus 35% in the placebo group) and drank more fluid afterward.⁹ A primary care trial confirmed similar results in a community setting, with vomiting within four hours dropping from about 43% to 20% after a single dose.¹⁰

Ondansetron is a prescription medication, so you would need to contact your child’s doctor to get it. It is generally used for children who cannot keep any fluid down and are heading toward dehydration. It is not a first-line remedy for every stomach bug.

As for anti-diarrheal medications like loperamide (Imodium), these should generally be avoided in young children. A systematic review found that in children under three years old, as well as in children who are malnourished, moderately or severely dehydrated, or who have bloody diarrhea, the adverse effects of loperamide outweigh any benefit, even at low doses.¹¹ Serious side effects including intestinal paralysis and drowsiness have been reported. The diarrhea itself, unpleasant as it is, is part of the body’s mechanism for flushing the pathogen out.

What About Probiotics?

Probiotics are live microorganisms sold as supplements or found in certain yogurts, and they have been studied extensively for childhood diarrhea. The evidence is uneven. Not all probiotic strains are equally effective, and some widely sold products have shown little measurable benefit.

One clinical trial compared five different probiotic preparations head to head. Lactobacillus rhamnosus GG and a specific four-strain mix shortened the median duration of diarrhea from about 115 hours to roughly 70 to 79 hours compared with oral rehydration alone. The other three preparations tested in the same trial did not meaningfully affect outcomes.¹² A meta-analysis of multiple trials found that Saccharomyces boulardii and Lactobacillus reuteri had statistically significant effects on diarrhea duration, while Lactobacillus rhamnosus GG and Lactobacillus acidophilus did not reach significance when pooled across studies.¹³

The practical upshot: if you want to try a probiotic, look for a product containing Saccharomyces boulardii or Lactobacillus reuteri, as those have the most consistent trial support for shortening diarrhea. Probiotics are not harmful in otherwise healthy children, but they are not a substitute for fluid replacement. Think of them as a possible add-on, not the main treatment.

Zinc Supplements in Context

The World Health Organization recommends zinc supplementation for children with acute diarrhea in low- and middle-income countries, where zinc deficiency is common. The rationale is well-supported: a meta-analysis found that zinc reduced both diarrhea duration (by about 15%) and stool frequency (by about 19%) compared with placebo.¹⁴ An early trial in India showed a roughly 23% reduction in the risk of continued diarrhea with zinc, with the biggest benefits appearing after the third day and in children with stunted growth.¹⁵

A large multicenter trial later confirmed that lower doses (5 mg or 10 mg) performed about as well as the standard 20 mg dose, meaning even a small dose could help without causing the nausea that zinc sometimes triggers in children.¹⁶ For families in high-income countries where zinc deficiency is less prevalent, routine zinc supplementation during a stomach bug is not standard practice. But if your child is a picky eater or has a diet low in zinc-rich foods (meat, beans, seeds), it may be worth discussing with your pediatrician.

Feeding During and After the Illness

There is a longstanding belief that you should starve a stomach bug or restrict food to bland items like bananas, rice, applesauce, and toast (the so-called BRAT diet). Current evidence does not support prolonged food restriction. Children who resume a normal, age-appropriate diet as soon as they can tolerate it tend to recover faster. One children’s hospital that implemented evidence-based guidelines saw the proportion of admitted patients who advanced to a regular diet by discharge jump dramatically over two years, from under 5% to over 75%, without adverse outcomes.¹⁷

For breastfed infants, continue breastfeeding throughout the illness. Breast milk provides fluid, calories, and immune factors that help with recovery. For formula-fed infants, continue formula as tolerated. If your child is too nauseated to eat, do not force it, but offer small amounts of food once the vomiting subsides. Complex carbohydrates, lean meats, fruits, vegetables, and yogurt are all reasonable. Sugary drinks, full-strength fruit juice, and greasy or heavily spiced foods tend to make things worse.

Temporary Lactose Trouble After a Stomach Bug

Here is something many parents do not expect: even after the virus is gone, your child may have loose stools or gassiness for a week or two when they drink milk. This happens because the infection temporarily damages the cells lining the small intestine that produce lactase, the enzyme needed to break down lactose (the sugar in milk). Until those cells regrow, lactose passes through undigested and can provoke diarrhea, bloating, and cramping.

A Cochrane systematic review found that switching to lactose-free products during and shortly after acute diarrhea shortened the duration of illness by an average of about 18 hours and roughly halved the rate of treatment failure (meaning ongoing diarrhea or worsening symptoms) compared with regular lactose-containing products.¹⁸ If your child seems to be recovering but then has a relapse of loose stools after reintroducing milk, switching to a lactose-free milk or yogurt for a week or so often resolves the issue. This is not a permanent intolerance; the gut lining usually repairs itself within two to four weeks.

Keeping the Rest of the Household Healthy

Viral gastroenteritis is highly contagious. The most common causative agent in children is rotavirus, though norovirus, adenovirus, and other pathogens contribute as well.¹⁹ These viruses spread through stool and vomit, and norovirus in particular can survive on surfaces for days. Within households, gastrointestinal illness spreads readily: one study tracking over 200 families found a secondary transmission rate of 0.35 gastrointestinal illnesses per susceptible person-month during the study period, meaning it jumped frequently from the sick child to other family members.²⁰

Handwashing with soap and water is the most reliable prevention. Alcohol-based hand sanitizers are effective against many pathogens but less reliable against norovirus specifically, because norovirus is a non-enveloped virus that resists alcohol. For surfaces, a dilute bleach solution (about one tablespoon of household bleach per gallon of water) is effective. Wash contaminated clothing and bedding on a hot cycle. The sick child should not share towels, cups, or utensils, and ideally should use a designated bathroom if your home has more than one.

Home Remedies and What to Avoid

In many cultures, herbal teas or traditional remedies are the first thing offered to a child with diarrhea. While some of these may be harmless, there is a lack of controlled evidence for safety and effectiveness in young children. Community health research has highlighted the risk of relying on unproven herbal treatments for childhood diarrhea, particularly when they delay proven interventions like oral rehydration.²¹

A few specific things to avoid:

• Sports drinks: these contain too much sugar and not enough sodium for a child with significant fluid losses. They are fine for mild cases in older children who refuse everything else, but they should not be the primary rehydration tool.
• Flat cola or ginger ale: a common home remedy, but the sugar content is very high and the electrolyte content is negligible. These can worsen diarrhea through osmotic effects.
• Homemade salt-sugar mixtures: getting the ratio wrong is easy and can be dangerous, especially for young children. A commercially prepared oral rehydration solution is safer.
• Anti-diarrheal medications in young children: as covered above, loperamide and similar drugs carry real risks in this age group.

Managing Your Own Anxiety

Watching your child retch and produce watery stools for hours is stressful, and it is normal to feel panicked. Research into what helps and hinders parents managing gastroenteritis at home has found that caregiver anxiety, insecurity, and the need for reassurance are among the biggest barriers to effective home management. On the flip side, practical support like information sheets with clear warning signs, and follow-up phone calls from a nurse, significantly improved parents’ confidence and reduced unnecessary emergency visits.²²

Having a written list of dehydration warning signs (the four-sign checklist described earlier works well) taped to the fridge can help you make calmer decisions at 2 a.m. Know your pediatrician’s after-hours number and whether your insurance covers telehealth visits. Most gastroenteritis episodes in children peak within 24 to 48 hours and resolve within three to five days. The illness feels longer than it is when you are in the middle of it, doing laundry every few hours and counting wet diapers. But the vast majority of children recover fully with nothing more than patience, fluids, and a gradual return to normal eating.