Gastroenteritis is a general term for infection or irritation of the digestive tract, particularly the stomach and intestine. It is frequently referred to as stomach or intestinal flu, although the influenza virus does not cause this illness.

Major symptoms include nausea, vomiting, diarrhea, and abdominal cramps. Fever and overall weakness sometimes accompany these symptoms. Gastroenteritis typically lasts about three days. Adults usually recover without problem, but children, the elderly, and persons with an underlying disease are more vulnerable to complications such as dehydration.


Gastroenteritis is an uncomfortable and inconvenient ailment, but it is rarely life-threatening in the United States and other developed nations. However, in the United States an estimated 220,000 children younger than age five are hospitalized annually with gastroenteritis symptoms. Of these children, 300 die as a result of severe diarrhea and dehydration. In developing nations, diarrhea- related illnesses are a major source of mortality. In 1990, approximately three million deaths occurred worldwide as a result of diarrheal illness.

Viral gastroenteritis

Gastroenteritis is usually caused by infection with one of these viruses: rotavirus, adenovirus, astrovirus, calicivirus, and small round-structured viruses (SRSVs). These viruses are found all over the world and are particularly problematic where sanitation is poor.

Typical exposure to these viruses occurs through the fecal-to-oral route, by ingesting food that is contaminated with fecal material or by coming in contact with an infected person’s vomit or diarrhea and then inadvertently bringing the contaminant to the mouth. Other routes of transmission are quite likely, because exposure to as few as 100 virus particles can cause an infection.

Typically, children are more vulnerable to rotaviruses— the most common cause of acute watery diarrhea. It is estimated that each year rotaviruses cause 800,000 deaths worldwide in children younger than age five. For this reason, much research has gone into developing a vaccine to protect children from this virus. Adults can be infected with rotaviruses, but these infections typically have minimal or no symptoms.

Adenoviruses and astroviruses are minor causes of childhood gastroenteritis, and children may become infected with caliciviruses and SRSVs. Adults experience illness from astroviruses as well, but the major causes of adult viral gastroenteritis are the caliciviruses and SRSVs. The SRSVs are a type of calicivirus and include the Norwalk, Southhampton, and Lonsdale viruses. SRSVs are the most likely to produce vomiting as a major symptom.

Bacterial gastroenteritis

Bacterial gastroenteritis is frequently a result of poor sanitation, the lack of safe drinking water, or contaminated food—conditions that are common in developing nations. Natural or man-made disasters can worsen underlying sanitation and food-safety problems. In developed nations, modern food production, handling, and distribution systems and methods may expose millions of people to disease-causing bacteria.

Common types of bacterial gastroenteritis can be linked to Salmonella and Campylobacter bacteria; however, Escherichia coli 0157 and Listeria monocytogenes are creating increased concern in developed nations. Cholera and shigella remain two diseases of great concern in developing countries, and research to develop long-term vaccines against them is underway.

Causes & symptoms

Gastroenteritis arises from ingestion of viruses, certain bacteria, or parasites. Spoiled food may also cause illness. Certain medications and excessive alcohol can irritate the digestive tract to the point of inducing gastroenteritis. Regardless of the cause, the symptoms of gastroenteritis include diarrhea, nausea, vomiting, abdominal pain, and cramps. Sufferers may also experience bloating, low fever, and overall tiredness. Typically, the symptoms last only two to three days, but some viruses may last up to a week.

A typical bout of gastroenteritis should not require a visit to the doctor. However, medical treatment is essential if symptoms worsen or if there are complications. Infants, young children, the elderly, and persons with underlying disease require special attention in this regard.

Dehydration is the greatest danger presented by gastroenteritis. The loss of fluids through diarrhea and vomiting can upset the body’s electrolyte balance, leading to potentially life-threatening problems, such as heart beat abnormalities (arrhythmia). The risk of dehydration increases the longer that symptoms are present. Signs of dehydration include a dry mouth, increased or excessive thirst, or scanty urination.

Symptoms that do not clear up within a week may point to an infection or disorder more serious than gastroenteritis. Symptoms of great concern include a fever of 102°F (38.9°C) or above, blood or mucus in the diarrhea, blood in the vomit, and severe abdominal pain or swelling. Persons experiencing these symptoms should seek prompt medical attention.


The symptoms of gastroenteritis are usually sufficient for identifying the illness. Unless there are complications or there is an outbreak that affects several people, identifying the specific cause of the illness is not a priority. However, if it is necessary to identify the infectious agent, a stool sample will be collected and analyzed for the presence of viruses, disease-causing (pathogenic) bacteria, or parasites.


Gastroenteritis is a self-limiting illness that will resolve by itself. Symptoms of uncomplicated gastroenteritis can be relieved with adjustments in diet, herbal remedies, and homeopathy. An infusion of meadowsweet (Filipendula ulmaria) may be effective in reducing nausea and stomach acidity. Once the worst symptoms are relieved, slippery elm (Ulmus fulva) can be used to calm the digestive tract.

The homeopathic remedies Arsenicum album, ipecac, and Nux vomica are also believed to relieve the symptoms of gastroenteritis. In Chinese herbal medicine, the patent remedies Po Chai and Pill Curing can be effective for relieving nausea and diarrhea.

Supplementing the bacteria that are beneficial to a person’s health (probiotics) is recommended during the recovery phase of gastroenteritis. Specifically, live cultures of Lactobacillus acidophilus are said to be effective in soothing the digestive tract and returning the intestinal flora to normal.

In fact, in 2002, a new study found it was reasonably effective in treating children with acute infectious diarrhea. L. acidophilus is found in live-culture yogurt and in capsule or powder form at health food stores. Castor oil packs applied to the abdomen can reduce inflammation, spasms, and discomfort.

It is important to stay hydrated and nourished during a bout of gastroenteritis. In the absence of dehydration, it should be sufficient to drink generous amounts of nonalcoholic fluids, such as water or juice. Caffeine should be avoided, since it increases urine output.

The traditional BRAT diet—bananas, rice, applesauce, and toast—is tolerated by the tender gastrointestinal system, but it is not particularly nutritious. Many, but not all, medical researchers recommend a diet that includes complex carbohydrates (rice, wheat, potatoes, bread, and cereal, for example), lean meats, yogurt, fruit, and vegetables.

Milk and other dairy products shouldn’t create problems if they are part of the normal diet. Fatty foods or foods with a lot of sugar should be avoided. These recommendations are based on clinical experience and controlled trials, but are not universally accepted.

Allopathic treatment

Over-the-counter medications such as Pepto Bismol are useful in relieving the symptoms of gastroenteritis. These medications work by altering the intestine’s ability to move or secrete spontaneously, by absorbing toxins and water, or by altering intestinal microflora. Some over-the-counter medicines use more than one element to treat symptoms, and this information should be included on the label.

If over-the-counter medications are ineffective, a doctor may prescribe a more powerful anti-diarrheal drug, such as motofen or lomotil. If pathogenic bacteria or parasites are found in the patient’s stool sample, medications such as antibiotics will be prescribed.

Minimal to moderate dehydration is treated with oral rehydrating solutions that contain glucose and electrolytes. These solutions are commercially available under names such as Naturalyte, Pedialyte, Infalyte, and Rehydralyte. If vomiting prevents the patient from taking a full dose of solution, he or she may better tolerate fluid taken in small, frequent amounts.

Should oral rehydration fail or severe dehydration occur, medical treatment in the form of intravenous (IV) therapy is required. IV therapy can be followed with oral rehydration as the patient’s condition improves. Once normal hydration is achieved, the patient can return to a regular diet.

Sometimes, a child’s dehydration is so severe that it requires hospitalization with IV therapy. However, a study published in 2002 informed pediatricians that often, rapid intravenous rehydration and rapid nasogastric hydration in the emergency department are safe and effective alternatives to hospitalization for many children with viral gastroenteritis. Not only does this save money, it also saves a child the more frightening experience of being in a hospital overnight and the routine laboratory testing he or she would endure in the hospital setting.

Expected results

Gastroenteritis usually clears up within two to three days and there are no long-term effects. If dehydration occurs, recovery is extended by a few days.


Gastroenteritis can be avoided by practicing good hygiene, which includes washing hands thoroughly after using the bathroom or coming in contact with an infected person, using disinfectants to clean areas the infected person has come in contact with, and washing infected linens in hot water. Making sure that food is well-cooked and unspoiled can prevent bacterial gastroenteritis, but may not be effective against viral gastroenteritis.