What Is Gastroenteritis?

Gastroenteritis, often referred to as "stomach flu" or "food poisoning," is an inflammation of the stomach and intestinal lining. It manifests through symptoms like vomiting, diarrhoea, nausea, and abdominal pain. This illness is typically triggered by bacterial or viral infections; and it may also be induced by exposure to certain chemicals. While generally not severe for healthy individuals, gastroenteritis can lead to dehydration and may cause more severe symptoms.

What Causes Gastroenteritis?

Gastroenteritis arises from the immune system's inflammatory response in the stomach and intestines to combat infections, such as:

Viral Infections

Viruses such as norovirus, rotavirus, and adenovirus are common causes of gastroenteritis, especially in children.

Bacterial Infections

Bacteria like Escherichia coli (E. coli), Salmonella, Campylobacter, and Shigella can lead to bacterial gastroenteritis, often resulting from contaminated food or water.

Parasitic Infections

Parasites like Giardia lamblia and Cryptosporidium can cause gastroenteritis, typically through ingestion of contaminated food or water.

How Is Gastroenteritis Transmitted?

Gastroenteritis is typically transmitted through:

Ingestion of Contaminated Food or Water

Consuming food or water contaminated with viruses, bacteria, or parasites can lead to gastroenteritis.

Person-to-Person Contact

Direct contact with an infected person, such as sharing utensils, food, or personal items, can transmit gastroenteritis.

Poor Hygiene Practices

Improper handwashing after using the restroom or before handling food can contribute to the spread of gastroenteritis.

Contact with Contaminated Surfaces

Touching surfaces or objects contaminated with infectious agents and then touching the mouth or face can transmit gastroenteritis.

Signs and Symptoms of Gastroenteritis

The symptoms of gastroenteritis are usually mild and resolve within 1-2 days, although in some instances, they may persist for up to 10 days. These symptoms commonly include:

  • Diarrhoea
  • Abdominal pain or cramping
  • Nausea
  • Vomiting
  • Fever

However, in rare instances, these symptoms can lead to dehydration and more severe complications. Prompt medical attention is necessary if you experience more serious symptoms such as:

  • Changes in mental state
  • Diarrhoea lasting for several days
  • High fever
  • Frequent vomiting
  • Severe abdominal pain
  • Stools containing blood or pus

How Is Gastroenteritis Diagnosed?

Gastroenteritis is typically diagnosed based on symptoms, activity history and medical history. In some cases, laboratory tests may be conducted, such as stool tests to detect bacteria, viruses, or parasites. Additionally, a physical examination may be performed to assess symptoms and rule out other conditions.

Treatments for Gastroenteritis

Treatment for gastroenteritis focuses on relieving symptoms and preventing dehydration. This may include:

Fluid Replacement

Drinking plenty of fluids, such as water, oral rehydration solutions, or clear broths, to replace lost fluids and electrolytes due to vomiting and diarrhoea.


Medications may help alleviate symptoms of diarrhoea and nausea, as well as to fight against the infection.

Dietary Recommendations

Gradually reintroduce bland, easy-to-digest foods like rice, bananas, toast, and applesauce once vomiting and diarrhoea have subsided. It is advisable to avoid spicy, fatty, or irritating foods that can exacerbate gastrointestinal symptoms.

How Can Gastroenteritis Be Prevented?

Preventing gastroenteritis involves practising good hygiene and food safety measures to reduce the risk of infection. Here are some preventive measures:

Hand Hygiene

Wash hands frequently with soap and water, especially after using the bathroom, changing diapers, and before preparing or eating food.

Food Safety

Ensure proper food handling, storage, and preparation. Cook foods thoroughly, avoid cross-contamination between raw and cooked foods, and refrigerate leftovers promptly.

Clean Water

Drink safe and clean water from reliable sources. Use boiled or filtered water if unsure about its quality, especially while travelling to areas with poor sanitation.

Personal Hygiene

Avoid sharing utensils, towels, or personal items with individuals who are sick. Stay home from work or school if experiencing symptoms of gastroenteritis to prevent spreading the infection to others.


Depending on the cause of gastroenteritis, vaccines may be available to prevent certain types of viral or bacterial infections.

Frequently Asked Questions (FAQs)

How long does food poisoning last?

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Why is it important to stay hydrated during gastroenteritis?

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When should I see a doctor for food poisoning?

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Dr Kieron Lim Image

Meet Our Gastroenterologist

Dr Kieron Lim

MBBS, University of LondonMember, Royal College of Physicians (UK)Fellow, Academy of Medicine (Gastroenterology) SingaporeFellow, Royal College of Physicians (Edinburgh)

Dr Kieron Lim is a senior consultant in Gastroenterology and Hepatology. With decades of specialist experience, he holds various leadership roles at Mount Elizabeth Hospital and is the President-Elect of the Gastroenterological Society of Singapore (GESS). Dr Lim graduated from St Bartholomew’s and The Royal London School of Medicine (UK) and completed his fellowship training at the Recanati/Miller Transplantation Institute, Icahn School of Medicine, Mount Sinai New York, USA. He was formerly the Head of the Division of Gastroenterology and Hepatology at the National University Hospital and has actively contributed to the research and advancement of the field.