Quick answer
What is gastroenteritis?
Gastroenteritis is a common tummy bug that causes diarrhoea and being sick. It is usually caused by a viral or bacterial infection and normally clears up within about a week. The main risk is dehydration, so the most important thing is to drink plenty of fluids while you recover.
What is gastroenteritis?
Gastroenteritis is inflammation of the stomach and bowel, usually caused by an infection — commonly called a “tummy bug” or, when caught from food, food poisoning. It is very common and, while unpleasant, usually clears up on its own without treatment.
Symptoms
The main symptoms are:
- diarrhoea
- feeling sick or being sick
- stomach cramps
- sometimes a mild fever, headache and aching limbs
Symptoms usually start suddenly and ease over a few days.
What causes it
Gastroenteritis is most often caused by viruses (such as norovirus) or bacteria, and sometimes by parasites. The germs spread very easily through contaminated food and water, surfaces, and close contact — which is why outbreaks happen in households, schools and care settings.
Self-care
Most people recover at home. The most important thing is to avoid dehydration:
- drink plenty of fluids, taking small frequent sips if you feel sick
- consider oral rehydration sachets, especially for the very young, older people, or severe symptoms
- rest, and eat when you feel able to — plain foods are often easiest at first
To avoid spreading it, wash your hands thoroughly, and stay off work or school until 48 hours after symptoms have stopped.
When to get help
Contact a GP or NHS 111 if you cannot keep fluids down, show signs of dehydration, have blood in your diarrhoea, a high fever, or symptoms lasting more than about a week. Babies, older or frail people, and anyone with a weakened immune system should seek advice sooner.
Common questions
- How long does gastroenteritis last?
- Most cases improve within a few days, with full recovery usually within about a week. Diarrhoea can sometimes last a little longer. If symptoms persist beyond this, get medical advice.
- How do I avoid dehydration with a tummy bug?
- Take small, frequent sips of water or squash even if you feel sick. Oral rehydration sachets from a pharmacy can help replace lost salts and fluids, especially for young children, older people, or if diarrhoea is severe.
- Is gastroenteritis contagious?
- Yes, very. It spreads easily through contaminated hands, surfaces and food. Wash your hands thoroughly with soap and water, and stay off work or school until at least 48 hours after symptoms stop.
- Should I take anything to stop the diarrhoea?
- Most people just need fluids and rest. Anti-diarrhoea medicines are not suitable for everyone and should not be used if there is blood in the stool or a high fever. A pharmacist can advise on what is appropriate for you.