Gastroenteritis in adults

Gastroenteritis is a very common condition that causes diarrhoea and vomiting. It’s usually caused by a bacterial or viral tummy bug.

Cases in adults are usually caused by norovirus (the ‘winter vomiting bug’) or bacterial food poisoning.

Gastroenteritis can be very unpleasant, but it usually clears up by itself within a week. You can normally look after yourself at home until you’re feeling better.

There is a separate page on gastroenteritis in children and babies.

Symptoms of gastroenteritis

 

The main symptoms of gastroenteritis are:

  • sudden, watery diarrhoea
  • feeling sick
  • vomiting, which can be projectile
  • a mild fever

Some people also have other symptoms, like:

The symptoms usually appear up to a day after becoming infected. They typically last less than a week, but can sometimes last longer.

When to get medical advice

You don’t normally need to see your GP if you think you have gastroenteritis. It should get better on its own.

Visiting your GP practice can put others at risk, so it’s best to phone 111 or your GP if you’re concerned or feel you need advice.

Immediate action required: Phone 999 or go to A&E if you:

  • vomit blood or have vomit that looks like ground coffee
  • have green vomit
  • may have swallowed something poisonous
  • have a stiff neck and pain when looking at bright lights
  • have a sudden, severe headache or stomach ache
  • have blue, grey, pale or blotchy skin, lips or tongue – on brown or black skin this may be easier to see on the palms of the hands or soles of the feet
  • are having severe difficulty breathing, or taking lots of quick, short breaths

Urgent advice: Phone 111 or your GP practice if you:

  • have symptoms of severe dehydration, like persistent dizziness, only passing small amounts of urine or no urine at all
  • have bloody diarrhoea
  • are vomiting constantly and are unable to keep down any fluids
  • have a fever over 38C (100.4F)
  • have diarrhoea for more than 7 days or vomiting for more than 2 days
  • have returned from a part of the world with poor sanitation in the past few weeks
  • you have a condition like kidney disease, inflammatory bowel disease or a weak immune system, and have diarrhoea and vomiting

Your GP may suggest sending off a sample of your poo to a laboratory to check what’s causing your symptoms. Antibiotics may be prescribed if this shows you have a bacterial infection.

What to do if you have gastroenteritis

If you experience sudden diarrhoea and vomiting, stay at home until you’re feeling better. There’s not always a specific treatment, so you have to let the illness run its course.

You don’t usually need to get medical advice, unless your symptoms don’t improve or there’s a risk of a more serious problem.

There are things you can do to help ease your symptoms.

Do

  • drink plenty of fluids to avoid dehydration – take small sips of water
  • take paracetamol if you’re in discomfort
  • get plenty of rest
  • eat when you feel able to – it may help to avoid foods that are fatty or spicy
  • speak to your pharmacist about using a rehydration drink if you have signs of dehydration like a dry mouth or dark urine

Don't

  • do not have fruit juice or fizzy drinks – they can make diarrhoea worse
  • do not give aspirin to children under 16

Read further information about treating dehydration

Read further information about treating diarrhoea in adults

Gastroenteritis can spread very easily. It’s important to wash your hands regularly while you’re ill.

Stay off work until at least 2 days after your symptoms have cleared, to reduce the risk of passing it on.

Treatment for gastroenteritis

A pharmacist can help with gastroenteritis.

Speak to a pharmacist if you:

  • have signs of dehydration, like dark, smelly pee or peeing less than usual
  • are an older person
  • have a weakened immune system
  • have other health conditions that increase your risk of dehydration
  • need to stop diarrhoea or vomiting for a few hours

They may recommend:

  • oral rehydration powder that you mix with water to make a drink
  • medicine to stop diarrhoea for a few hours, like loperamide (not suitable for children aged 11 years and under)
  • medicine to stop vomiting (antiemetics)
Find your nearest pharmacy

How gastroenteritis is passed on

The bugs that cause gastroenteritis can spread very easily from person to person.

You can catch the infection if small particles of vomit or poo from an infected person get into your mouth. This can happen through:

  • close contact with someone with gastroenteritis – they may breathe out small particles of vomit
  • touching contaminated surfaces or objects

Eating contaminated food can also put you at risk. This can happen if:

  • an infected person doesn’t wash their hands before handling food
  • you eat food that has been in contact with contaminated surfaces or objects
  • you eat food that hasn’t been stored and cooked at the correct temperatures

A person with gastroenteritis is most infectious from when their symptoms start until 48 hours after all their symptoms have passed. However, they may also be infectious for a short time before and after this.

How to prevent gastroenteritis

It’s not always possible to avoid getting gastroenteritis, but following this advice can help stop it spreading.

Do

  • stay off work until at least 48 hours after the symptoms have passed – avoid visiting anyone in hospital during this time too
  • wash your hands frequently and thoroughly with soap and warm water, particularly after using the toilet and before preparing food
  • disinfect any surfaces or objects that could be contaminated – it’s best to use a bleach-based household cleaner
  • wash contaminated items of clothing or bedding separately on a hot wash
  • flush away any poo or vomit in the toilet and clean the surrounding area
  • make sure food is properly refrigerated
  • always cook your food thoroughly

Don't

  • do not prepare food for other people when you’re infected, if possible
  • do not eat food that is past its use-by date
  • do not rely on alcohol hand gels, as they’re not always effective
  • do not share towels, flannels, cutlery or utensils while you are ill

Take extra care when travelling to parts of the world with poor sanitation, as you could pick up a stomach bug. For example, you may need to boil tap water before drinking it.