Medically Reviewed By William C. Lloyd III, MD, FACS
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What is gastroenteritis?

Gastroenteritis is a general term for irritation and inflammation of the gastrointestinal tract. The hallmark symptoms of gastroenteritis are nausea, vomiting and diarrhea. Gastroenteritis is quite common and can occur in any age group or population.

Gastroenteritis is most frequently caused by a viral infection and is commonly referred to as viral gastroenteritis, the stomach flu, or the 24-hour or 48-hour “bug.” This type of infectious gastroenteritis is contagious.

A bacterial infection, such as Salmonella food poisoning, can cause bacterial gastroenteritis, which is also contagious. Food poisoning is also known as food-borne illness. Every year 48 million Americans suffer from food-borne illnesses.

Similar gastrointestinal symptoms can also result from a variety of other conditions that are not contagious, such as alcohol intoxication or irritable bowel syndrome.

Gastroenteritis can lead to serious complications such as dehydration, especially in infants, young children, the elderly, or people with chronic diseases. The underlying disorder, disease or condition that is causing gastroenteritis can also cause complications.

Seek prompt medical care if you have symptoms of gastroenteritis that do not improve after a day or two. Seek immediate medical care (call 911) if you, your child, or someone you are with, have symptoms of gastroenteritis accompanied by lethargy, change in alertness, delirium, a seizure, rectal bleeding, or a lack of urination.

What are the symptoms of gastroenteritis?

The symptoms of gastroenteritis can range from mild to severe and may vary depending on the underlying cause. Symptoms of viral gastroenteritis, caused by a viral infection, generally resolve within 24 to 48 hours. Other causes of gastroenteritis can last longer.

Symptoms of gastroenteritis can include:

Serious symptoms that might indicate a life-threatening condition

Gastroenteritis can lead to serious or life-threatening complications in some cases, including dehydration and gastrointestinal bleeding. Seek immediate medical care (call 911) if you, your child, or someone you are with, are experiencing any of the following life-threatening symptoms:

  • Change in alertness or consciousness

  • Delirium

  • Extreme thirst

  • Lack of urination or fewer wet diapers in infants

  • Lethargy

  • Rectal bleeding

  • Seizure

  • Shallow, raspy, or difficulty breathing

  • Sunken fontanel (soft spot) in an infant’s head

  • Unresponsiveness

What causes gastroenteritis?

Gastroenteritis is most frequently caused by a gastrointestinal viral infection. Similar symptoms can also result from a variety of other conditions including:

  • Alcohol intoxication

  • Anthrax infection

  • Bacterial gastrointestinal infection, such as salmonella food poisoning, campylobacter infection, or traveler’s diarrhea

  • Dysentery

  • Indigestion

  • Irritable bowel syndrome

  • Medication side effects

  • Parasite infections, such as Giardia infection

  • Stress

  • Toxic ingestion, such as eating poisonous plants, mushrooms or chemicals

What are the risk factors for gastroenteritis?

A number of factors increase the risk of developing gastroenteritis. They include:

  • Close contact with a person who has viral gastroenteritis

  • Eating eggs or meats that are raw or undercooked

  • Eating excessively large meals, especially if consumed rapidly

  • Eating expired foods or leftovers that have been refrigerated for more than two to three days

  • Having a compromised immune system due to such conditions as HIV/AIDS, diabetes, kidney disease, or cancer or cancer treatment

  • High stress levels or anxiety

  • Ice cubes made from contaminated water
  • Not washing hands after contact with a person who has bacterial or viral gastroenteritis

  • Not washing hands frequently, especially after using the bathroom, touching pet feces, handling reptiles, or touching raw foods or foods potentially contaminated with bacteria or parasites or viruses

  • Taking certain medications, such as antibiotics and chemotherapy

Gastroenteritis can lead to the serious complication of dehydration in some cases. People most at risk for dehydration include:

  • Infants

  • People with chronic illnesses, such as diabetes or cancer

  • Small children

  • The elderly

Reducing your risk of gastroenteritis

Not all people who are at risk for gastroenteritis will develop the condition, but you can lower your risk of developing or transmitting gastroenteritis by :

  • Avoiding contact with a person who has food poisoning, gastroenteritis, or symptoms such as vomiting and diarrhea

  • Defrosting foods in the refrigerator or microwave, not on the counter

  • Drinking alcohol in moderation

  • Keeping poisonous or toxic plants or products out of reach of young children

  • Not keeping reptiles as pets in homes, especially with infants and young children

  • Not using ice cubes in beverages
  • Refrigerating or freezing leftovers right away and eating them within two to three days of refrigerating. Leftovers from restaurants should be eaten within 24 hours.

  • Throwing out expired food, old leftovers, or perishable food that has been sitting at room temperature for two hours or longer

  • Washing hands frequently during and after contact with a person who has food poisoning, gastroenteritis, or symptoms such as vomiting and diarrhea

  • Washing hands frequently, especially after using the bathroom, touching pet feces, handling reptiles, changing diapers, or touching raw foods

  • Washing plates, utensils, and cutting boards that have been exposed to raw meats or poultry in hot soapy water before reusing

How is gastroenteritis treated?

Treatment plans for gastroenteritis are individualized depending on the underlying cause and your age, medical history, and any other conditions you may have. Treatment generally involves a multifaceted plan that addresses the cause; minimizes the discomfort of nausea, vomiting, and diarrhea; and decreases the risk of dehydration.

When gastroenteritis is caused by a self-limiting condition, such as viral gastroenteritis, treatment includes:

  • Not eating solid foods to rest the stomach and intestines until symptoms have passed

  • Drinking plenty of fluids (water or rehydrating fluid, such as Pedialyte) to ensure adequate hydration

In some cases, medications are used to treat gastroenteritis. Antibiotics may be prescribed when gastroenteritis is caused by a bacterial infection, such as in bacterial food poisoning due to Shigella, Salmonella, or Campylobacter infection.

Treatment of severe gastroenteritis that does not resolve or leads to dehydration may require hospitalization and rehydration with intravenous fluids.

What are the possible complications of gastroenteritis?

Complications of gastroenteritis can be serious, even life threatening in some cases. Complications can include:

  • Severe dehydration, which can lead to an electrolyte imbalance and shock

  • Aspiration, which is when contents of the stomach flow into the lungs during vomiting (a rare occurrence)

  • ·A rip in the esophagus (Mallory-Weiss tear) due to multiple violent episodes of retching and vomiting (a rare occurrence)

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 19
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Gastroenteritis, Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  2. Viral gastroenteritis. Centers for Disease Control.
  3. Bresee JS, Marcus R, Venezia RA, et al. The etiology of severe acute gastroenteritis among adults visiting emergency departments in the United States. J Infect Dis 2012; 205:1374.