Gastroenteritis Fact Sheet

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The Stomach Flu

Gastroenteritis is an illness in which the stomach and intestines become inflamed due to an infection. It is characterized by a range of possible symptoms, from diarrhea to vomiting. When people say they have the stomach flu, they are describing this gastrointestinal disease. It is not related to the actual flu, or influenza, but it is a common enough problem that many people have experienced the stomach ‘bug’ at some point in their lives.

While gastroenteritis can be a one or two day illness for many, it is also a disease that should be taken seriously, especially for those with weaker immune systems. Find out what you need to know about this illness with this gastroenteritis fact sheet.


The stomach flu may be caused by a bacterial, viral, or parasitic infection. Examples of bacteria that can cause gastroenteritis include Escherichia coli, which is often behind cases of food poisoning or a stomach flu that traveler’s sometimes experience when visiting another country. Salmonella is a bacteria someone can be exposed to when handling raw poultry. Campylobacter may be present in raw meat and unpasteurized milk. Bacterial infections of the stomach and intestines usually last for one week, although they can persist beyond that time frame.

Common viruses that may be the cause of a stomach flu include astroviruses, adenoviruses, and rotaviruses. They are responsible for about one-third of cases of gastroenteritis in children. Viral infections are very contagious and can easily be spread from close contact. They usually only last for a day or two. Parasitic infections are usually contracted through contaminated water. They are much less common then bacterial and viral infections.

Gastroenteritis also can be caused by bacteria already present in the gastrointestinal tract which flourish when stomach’s pH is altered by the use of some medications or antacids. Antibiotics, laxatives, steroids, aspirin, and nonsteroidal anti-inflammatory drugs can all be behind a stomach bug. Other possible causes include lactose intolerance and an exposure to toxins.


The symptoms of gastroenteritis revolve around disturbances with the gastrointestinal tract. The following are all possible symptoms:

  • Diarrhea
  • Vomiting
  • Nausea
  • Abdominal cramping
  • Fever
  • Dehydration

Diarrhea and vomiting for more than two days, blood in the vomit or stool, a fever above 101 degrees, and dehydration are all more serious symptoms of the stomach flu. Dehydration in particular is what can make this disease very dangerous. Fluids are lost during a fever and from diarrhea and vomiting, so it is important to replenish those fluids throughout the illness. If you are experiencing serious symptoms it is important to see your doctor.


How is the stomach flu treated? In mild cases it is possible to simply take in fluids to stay hydrated and to correct an electrolyte imbalance. Drink fluids that contain electrolytes in addition to water. Water alone will not replace lost electrolytes. For children this includes drinks such as Pedialyte and Rehydrate. Adults can drink fruit juices, ginger ale, and Gatorade. Solid foods should be bland, such as rice, applesauce, toast, bananas, and pasta. Start solid foods once vomiting has stopped. If vomiting continues for 48 hours, you need to go to the doctor’s.

How is gastroenteritis treated if the body cannot overcome the infection on its own? There are medications to stop the diarrhea or vomiting, which may or may not be prescribed. Antibiotics can be used in many cases once the cause is identified. If necessary treatment may also involve rehydration with an IV.


Gastroenteritis is a fairly common disease. Bacterial, viral, and parasitic infections are contagious. A stomach flu caused by exposure to toxins, food allergies, or the use of medications is not. To avoid becoming ill it is important to wash hands regularly and to avoid food and water that may be contaminated. Staying in good health and eating a healthy diet is also beneficial for maintaining a strong immune system that will be able to deal with an infection.

After reading through the gastroenteritis fact sheet you can have an idea of what to do in the case of a stomach flu. While this is a common health problem, it is easy to treat and in many cases is a mild disease. The danger is if someone become dehydrated. If symptoms persist and there is the possibility of dehydration, always seek medical attention.