Gastroenteritis is an inflammation or irritation of the lining of the stomach and intestines which often results in diarrhea, nausea, vomiting or stomach cramps. In healthy adults, gastroenteritis is not usually a serious condition. However, the condition can cause life-threatening dehydration or electrolyte imbalance in infants and children.

Although gastroenteritis causes relatively few child fatalities in the United States, its role in promoting acute diarrhea makes it the leading cause of death among children worldwide. It can also be fatal in adults who are unable to care for themselves. People with medical conditions or weakened immune systems may be at risk for developing severe gastroenteritis.

Gastroenteritis is most often caused by viruses spread by close contact with an infected person, or by consuming food contaminated by bacteria. The condition can also be caused by parasites, protozoans, chemicals or toxins. Certain types of medications may also cause non-contagious types of gastroenteritis.  

Children often contract a virus when they put their fingers in their mouths after touching something contaminated with the virus. Or, they may contract bacterial infection by eating mayonnaise, dairy products, meat and other foods that have been left unrefrigerated. Infection with parasites or protozoans may occur when a child consumes contaminated water and food or swims in water infected by these organisms.

In many cases, children with gastroenteritis recover after several days without consulting a physician. Gastroenteritis may be diagnosed during a physical examination that includes a medical history. If patients have been experiencing symptoms for 48 hours or longer, physicians may request a stool sample, which will be examined in a laboratory under a microscope to detect the presence of bacteria, parasites or other substances that may be causing the illness.

Mild cases of gastroenteritis may be treated at home by increasing fluid intake to avoid dehydration. This is particularly important for children, who become dehydrated faster than adults. More severe cases may require hospitalization where patients are given fluids intravenously (through a vein).