Bacterial gastroenteritis in children


What Is It?

Gastroenteritis is an inflammation of the stomach and intestines that produces diarrhea, vomiting, nausea and other symptoms of digestive upset. In the industrialized world, the most common causes of gastroenteritis in children are viruses, bacteria (food poisoning), and intestinal parasites.

  • Viral gastroenteritis — In otherwise healthy children, viral infections of the digestive tract often are responsible for mild episodes of gastroenteritis. Rotaviruses, adenoviruses, enteroviruses (during summer months), astroviruses and Norwalk virus are currently the most common causes of viral gastroenteritis in children in the United States. All of these viruses tend to spread on hands that have touched either an infected person’s stool or surfaces contaminated with infected stool. For this reason, young children — especially those just starting to learn good hygiene — are particularly vulnerable to viral gastroenteritis. They may touch a dirty diaper (either their own or a playmate’s), forget to wash their hands after using the toilet, put dirty fingers in their mouths, bite their fingernails, or chew and suck on toys that other children have touched with soiled hands. Parents and child-care personnel also can spread viral gastroenteritis from child to child, particularly if they do not wash their hands thoroughly after changing every soiled diaper. In addition, adults who have viral gastroenteritis themselves sometimes can spread their viral infections to children, especially if they prepare children’s meals without first washing their hands. Occasionally, some of the viruses that cause viral gastroenteritis also have been found in drinking water or food, primarily in developing countries and rural areas where sanitation is poor.
  • Bacterial gastroenteritis (food poisoning) — Food that has been prepared or stored improperly can grow bacteria on its surface, and these bacteria sometimes produce irritating chemicals called toxins. If a child eats the germ-filled food, symptoms of gastroenteritis are triggered either by the bacteria themselves or by their irritating byproducts. In addition, certain types of aggressive bacteria (such as campylobacter, salmonella, or E. coli 0157) can cause more severe forms of food poisoning that produce high fever, severe gastrointestinal symptoms and dehydration, even in children who are usually strong and healthy.
  • Intestinal parasites — Like the agents that cause viral gastroenteritis, intestinal parasites can be spread to children on dirty hands, on the soiled surfaces of toys and bathroom fixtures, and in contaminated water or food. Giardia lamblia, the parasite that causes giardiasis, is the most common parasitic cause of diarrhea among children in the United States, especially those in child-care centers.

Worldwide, gastroenteritis claims the lives of 3 million to 5 million children every year, primarily in developing nations where sanitation and health care are poor. Most of these children die from extreme dehydration (abnormally low levels of body water) resulting from a combination of severe diarrhea, vomiting and insufficient intake of fluids. Even in the industrialized world, millions of episodes of gastroenteritis occur each year, especially in young children. In the United States, rotavirus infections — the most likely cause of infectious diarrhea in children under age 5 — are responsible for more than 3 million cases of gastroenteritis in children each year, with at least 50,000 hospitalizations and 20 to 40 deaths.

Overall, about 90 percent of children with gastroenteritis in the United States have such mild symptoms that their parents do not need to take them to a doctor. Occasionally, however, gastroenteritis can lead to severe dehydration and other dangerous complications, especially in high-risk children, including infants, children with chronic illnesses and children taking immune-suppressing medications.


In children, symptoms of gastroenteritis include mild diarrhea, abdominal pain, cramps, vomiting, irritability (fussiness) and poor appetite. Some children also have a low-grade fever or complain of a headache.


To help make a diagnosis, your doctor may ask the following questions:

  • Has your child been exposed to an adult or child with diarrhea, especially in a day-care center or preschool setting?
  • Has your child played with a pet that is ill with gastrointestinal symptoms like diarrhea?
  • Has your child touched pet reptiles? Reptiles, especially pet turtles, sometimes carry salmonella bacteria.
  • Has your child recently traveled to a developing country or been in any location where the drinking water is not tested routinely or been near potentially contaminated streams, lakes or swimming holes in the United States?
  • Has your child recently drunk unpasteurized milk or apple cider, eaten unwashed vegetables or eaten food that was left standing at room temperature for prolonged periods?

To help assess your child’s risk of dehydration, your doctor also may ask questions related to your child’s fluid intake and fluid losses over the past several hours. Specifically, you doctor may want to know about:

  • The number of episodes of vomiting
  • Whether your child can drink fluids without vomiting
  • The number of bowel movements
  • The fluid content of your child’s bowel movements (are stools semi-solid, mildly “loose” or very watery?)
  • Frequency of urination, often measured as the number of wet diapers within the last eight to 12 hours, or the number of bathroom trips (for urination, not diarrhea)

In most cases, a doctor diagnoses gastroenteritis and any associated dehydration based on the symptoms, history of exposure to someone with diarrhea, spoiled food or impure water, and the results of a physical examination. Special laboratory testing rarely is needed unless your child has unusually severe symptoms, such as:

  • A high fever or fever that lasts longer than several days
  • Severe, watery diarrhea
  • Signs of significant dehydration, including dry mouth, eyes and skin; no tears when crying; no wet diapers within the past 12 hours; a sunken “soft spot”; a weak cry; unusual sleepiness or lack of body movement; and a sudden drop in weight, which can happen with the loss of body fluids in young children
  • Stool that contains blood or pus
  • Diarrhea that lasts more than two weeks

This testing may include blood tests to check for evidence of infection and dehydration, as well as other laboratory tests, such as a stool culture. In the lab, stool samples may be cultured for the presence of bacteria (especially campylobacter, salmonella, or, less commonly, E. coli 0157) or examined for microscopic parasites.

Expected Duration

In children, most cases of mild, uncomplicated gastroenteritis last about two to three days. However, even after symptoms subside, your child may continue to have occasional loose stools for more than a week.


To help prevent gastroenteritis in all members of your family, you can take the following steps:

  • Wash your hands frequently, especially after using the toilet, after changing diapers and after caring for a child with diarrhea.
  • Wash your hands before and after preparing food, especially after handling raw meat.
  • Wash diarrhea-soiled clothing in detergent and chlorine bleach. If bathroom surfaces are contaminated with stool, wipe them with a chlorine-based household cleaner.
  • Cook all meat thoroughly before you serve it to your family, and refrigerate leftovers within two hours.
  • Make sure you don’t transfer cooked foods onto unwashed plates that held raw meat.
  • Wash kitchen countertops and utensils thoroughly after they have been used to prepare meat.
  • Never drink unpasteurized milk, unpasteurized apple cider or untreated water.
  • If you travel to an area where sanitation is poor, make sure that your family drinks only bottled water or soft drinks, and that they don’t eat ice, uncooked vegetables or fruit that they haven’t peeled themselves.

If your child attends day care, make sure that all day-care personnel wash their hands frequently, especially after changing soiled diapers and before preparing children’s food. Also, check that your center follows pediatricians’ standard recommendations for managing cases of diarrhea:

  • If a child develops diarrhea while in day care, notify the parent or guardian to take the child home as soon as possible.
  • Do not allow the sick child to return to day care until diarrhea has begun to improve.


In otherwise healthy children, most cases of mild gastroenteritis gradually resolve within a few days. In the meantime, you can try the following suggestions:

  • To prevent dehydration, encourage your child to drink plenty of fluids. Your doctor may recommend a particular brand of over-the-counter oral rehydration solution in addition to breast milk, formula or milk. In general, these solutions are better than soft drinks, fruit juice or other sweetened beverages, which usually have too many carbohydrates and too little sodium to restore normal fluid balance in children with gastroenteritis.
  • If your child is too nauseated to drink his or her normal intake of fluids at one sitting, try offering several smaller sips more frequently over a longer period.
  • Once your child’s vomiting subsides, resume a normal diet gradually while continuing the oral rehydration solution. Begin with lean meats and complex carbohydrates, such as rice, potatoes and bread. Temporarily avoid fatty foods and sugary beverages. If your child is breast-feeding, resume nursing as soon as possible.
  • Do not give your child anti-diarrhea medicines without checking with the doctor first. These medicines can interfere with the intestine’s ability to pass harmful viruses, bacteria, parasites and toxins out of the body through the stool.
  • Have your child rest in bed until symptoms subside. Do not allow your child to return to school until diarrhea has begun to improve.

If your child is showing signs of significant dehydration and cannot take fluids by mouth, your doctor will send him or her to the hospital to receive fluids intravenously (through a vein). Your child also may need to take antibiotics if stool tests confirm that a more serious bacterial infection is causing the gastroenteritis. For intestinal parasites, your doctor will prescribe an antimicrobial medication.

When To Call A Professional

Call your doctor promptly whenever an infant less than 2 months old has symptoms of gastroenteritis. For older children with diarrhea and vomiting, call your doctor if your child has any one of the following:

  • Stools that contain blood or pus, or stools that are foul-smelling
  • Signs of dehydration
  • Blood or bile (greenish fluid) in the vomit
  • Severe abdominal pain or a swollen (distended) abdomen
  • A history of recent travel to a developing country or to any area where sanitation is poor
  • A chronic medical condition, especially any condition that weakens the immune system or is treated with immune-suppressing medication

Also, call your doctor promptly if your child is taking any oral medication for a chronic medical condition and is either too nauseated to swallow the medicine or has vomited after taking it. Do not repeat any vomited doses of medicines without contacting your child’s doctor.


Overall, the prognosis is excellent. Almost all children with mild gastroenteritis recover completely without complications.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.