The time between catching the infection and the start of symptoms (the incubation period) depends on the type of infection you have. It can range from one hour to a few weeks but it's usually between one and three days.
You may have symptoms including:
- diarrhoea, which may contain blood and mucus, or be watery, greasy or frothy
- feeling sick or vomiting
- abdominal cramps, bloating, stomach rumbling or pain
- loss of appetite
- a fever
The time it takes to recover depends on what infection you have. Most people recover fully within approximately 10 days, although you’re likely to start feeling better sooner than that. However, severe infections, which are uncommon in the UK, may last for many weeks. It's important to go to your GP if your symptoms last for more than a week, or if you have recently travelled abroad.
For children with gastroenteritis, diarrhoea usually lasts for five to seven days and stops within two weeks, and vomiting usually lasts for one to two days, stopping within three days. If the symptoms continue for longer than this, see your GP.
In adults and older children, the symptoms of gastroenteritis may be confused with other conditions, such as ulcerative colitis.
Your GP will ask about your symptoms and examine you. He or she will ask how often you have vomited, about the frequency and consistency of your bowel movements, how much urine you’re passing, whether you have any blood in your faeces and if you have been able to keep down any food or drink.
Your GP may also ask about your medical history or if you have been in recent contact with someone who had diarrhoea or vomiting. He or she may also ask you whether you work with food or if you have eaten anything – either at home or in a restaurant – that might have been contaminated.
It's important to tell your GP if you have been travelling, including which countries you have visited and any vaccinations you had. Your GP may ask you for a sample of faeces to send for laboratory testing.
If you have gastroenteritis, you’re likely to be infectious to others. Stay at home and don’t go into work for at least 48 hours or until your symptoms get better. Keep your children off school until their symptoms have gone.
The most important thing to do is replace the fluids and salts you have lost to prevent dehydration. If you have mild gastroenteritis, drinks such as water and squash will help to keep you hydrated – don’t have fizzy or caffeinated drinks, or fruit juice until you have recovered. If you feel well enough, you can have small, light meals but don't have fatty or spicy foods.
If you have a more severe infection, use an oral rehydration solution (eg Dioralyte). This is a powder that is made up into a solution by adding water. It contains the right balance of sugars and salts for your body to encourage rehydration. You may find it better to stick to plain foods such as rice or toast until you feel that you can eat as usual. See our frequently asked questions for more information.
Certain probiotics (foods containing ‘good’ bacteria that occur naturally in your body) can help to reduce the duration of diarrhoea. However, not all types are effective at improving symptoms and it will also depend on what caused your gastroenteritis. See our frequently asked questions for more information.
If your baby has gastroenteritis and you're breastfeeding, continue to breastfeed if possible – see your GP if your baby can’t breastfeed. Don’t give your child anything to eat until he or she can drink enough and is fully rehydrated.
If gastroenteritis is causing you pain, take an over-the-counter painkiller, such as paracetamol or ibuprofen.
Medicines to stop diarrhoea such as loperamide (eg Imodium) are only recommended for adults and children over four years old. These medications slow down the action of your bowels so the contents take longer to pass through. Diarrhoea is only prevented temporarily while you’re taking these medicines but they are useful, for example, if you need to travel and won't be near a toilet. Don’t take these medicines if you have blood or mucus in your faeces or you have a high fever.
Your GP may prescribe you a medicine to help you stop being sick called an anti-emetic. Antiemetics can be helpful if you have severe vomiting.
Gastroenteritis caused by viruses can't be treated with antibiotics so your GP won't usually prescribe them. However, if your GP suspects that you have a bacterial infection, he or she may ask you for a faeces sample to send for laboratory testing, particularly if you have been travelling recently, work with food or could have developed food poisoning. The results will help to determine if you can be treated with antibiotics.
Always read the patient information that comes with your medicine and if you have any questions, ask your pharmacist for advice.
If you have lost so much fluid that you're very dehydrated, you may need to be admitted to hospital so that fluids can be replaced directly into your bloodstream via a catheter into your vein (intravenously).
The main causes of gastroenteritis are infection with a virus, bacteria or parasite.
Viruses are a main cause of gastroenteritis, particularly in children. These include:
- rotavirus – this is the most common cause of severe symptoms in children
- norovirus – this is very contagious but the symptoms are usually mild
- adenovirus – this most commonly affects young children
Viral infections can be seasonal. There is a peak of rotavirus and norovirus infections during the winter months.
The most common cause of bacterial gastroenteritis is food poisoning. Different bacteria that cause food poisoning include Salmonella, Campylobacter and Escherichia coli (E. coli).
Parasites rarely cause gastroenteritis in the UK, but they are a major problem in less developed countries and you may get infected when abroad. Giardia is a common parasite that is found in water, soil and food.
Complications from gastroenteritis occur mainly in young children or in adults who are over the age of 65, people who have other long-term medical conditions or those who have a weakened immune system.
Possible complications of gastroenteritis include:
- dehydration – see our frequently asked questions for more information
- irritable bowel syndrome (IBS)
Contact your GP if you:
- have severe pain or pain that doesn't respond to over-the-counter painkillers
- have vomiting or diarrhoea that continues for more than a few days, or you can't drink or eat without being sick – this is particularly important if you can’t keep down fluids
- have blood or mucus in your diarrhoea
- have signs of dehydration, including a very dry mouth, muscle cramps, reduced urine, sunken eyes and, later, confusion or irritability
- have recently travelled abroad
- can't take medicines you usually take for other conditions without being sick
You can become infected with gastroenteritis in different ways. These include:
- in contaminated food, for example, when it’s not cooked thoroughly or is unpasteurised – see our frequently asked questions for more information
- from person to person – this happens if an infected person goes to the toilet and doesn't wash his or her hands properly afterwards, before handling food or touching other people
- contaminated items such as door handles and work surfaces
- in shellfish harvested from polluted waters
- in contaminated drinking water – in less developed countries this is how the majority of infections occur
- contact with a contaminated animal
The best way to reduce your risk of catching gastroenteritis is to always wash your hands with soap and water after going to the toilet. Make sure you also always wash your hands before and after preparing or eating food.
Make sure you have any necessary vaccinations before you travel to other countries and drink bottled water where necessary when you’re abroad. Don’t have ice in drinks unless you’re sure that the water is safe to drink.
If you have gastroenteritis, you can help to prevent spreading the infection to others.
- Hygienically dispose of, or properly clean, all soiled items such as towels or dirty nappies if your baby is ill.
- Wash soiled clothing or bed linen away from other laundry and at the highest temperature available (60°C or higher if possible). Only half fill the washing machine so that everything can be thoroughly cleaned and rinsed.
- Clean the toilet with disinfectant.
- Wipe toilet seats, flush handles, taps, surfaces and toilet door handles daily with hot water and disinfectant. Use a cloth that can be thrown away or one that is only used for this purpose.
- Don't share towels and flannels.
- Don't prepare food for others.
- Don’t go swimming for at least two weeks after your diarrhoea has stopped.
How can I prevent my child from getting gastroenteritis when we're abroad?
Food hygiene standards aren't always as high abroad. Also, you may encounter bacteria and parasites that your child hasn't been exposed to before. But by being prepared and careful about what your child eats and drinks while you're away, you can ensure that he or she stays healthy.
Although most children who get gastroenteritis have mild symptoms that clear up within a few days without treatment, getting gastroenteritis while abroad can be unpleasant and distressing for both you and your child, and interferes with your time away. To reduce the risks while on holiday, try to do the following.
- Ensure your child has any suggested vaccinations in enough time for your trip. Your GP or travel clinic will have an up-to-date list of these for the area you're visiting and how far in advance they need to be given.
- Only drink bottled water and check that the seal isn't broken when you buy it. Use bottled water for brushing teeth too. Don’t have ice in drinks if you’re unsure of where the water came from.
- Eat fruit that you can peel first and try not to eat salad leaves unless you have washed them yourself in bottled or sterilised water.
- Be cautious with shellfish and eggs (especially raw eggs in foods like mayonnaise), which are a common source of salmonella.
- Be cautious with takeaways or street food, unless you have seen it being properly cooked.
Before travelling abroad, think about what you can take with you in case your child does become ill. Oral rehydration salts (eg Dioralyte) can be extremely useful if your child becomes dehydrated. It's important to use clean, safe, drinking water when preparing the solution. Some types of probiotics may also be useful in relieving symptoms.
If you have any questions or concerns about gastroenteritis and you will be travelling, talk to your travel health adviser, GP or pharmacist before you go abroad.
How should I prepare food to prevent getting gastroenteritis or giving it to others?
Gastroenteritis is often caused by poorly prepared or stored food. Following good food hygiene measures can ensure that you, and the people you cook for, don't become ill.
To prevent gastroenteritis, it's important to maintain hygiene standards when preparing, cooking and storing food. The following food hygiene tips will help you to stay safe.
When preparing food, it's important to make sure that bacteria aren't spread. To prevent this:
- wash your hands before you start preparing food and after touching raw food (especially meat)
- check the use-by dates on food and that they have been stored properly
- prepare raw foods and foods that are ready to eat separately
- clean knives, chopping boards and counter tops thoroughly with hot, soapy water after using them to prepare raw meat or fish
- keep cloths, tea towels and hand towels clean, and wash or dispose of them regularly
- ensure meat and poultry is wrapped securely when stored in a fridge, so that meat juices don’t get into other food
- allow meat and poultry to thaw thoroughly before cooking
Thorough cooking destroys any harmful bacteria in your food so it's important to make sure you cook everything properly. Do this by:
- making sure your food is hot all the way through before you eat it – you can use a food thermometer to check
- never reheating food more than once
- serving cooked food on clean plates with clean utensils, not the same ones you used when preparing the raw food
Some foods need to be kept chilled in the fridge to keep them safe. When storing these types of food always:
- put them in the fridge straight away
- cool cooked foods as quickly as possible before putting them in the fridge
- use separate, sealed containers to store raw meat and poultry in your fridge
- use any stored and cooked leftovers within four days
If you have any questions or concerns about gastroenteritis and food hygiene, talk to your GP.
I have gastroenteritis, what should I eat?
If you have gastroenteritis, it's important to try to continue to eat as normal and drink enough fluids.
If you can, try to carry on eating as usual, but don’t have fatty foods, such as chips, fast foods, crisps and cakes, or spicy foods until you have recovered. Eat plain foods, such as rice, toast, dry cereal or crackers, until you feel that you can return to your usual diet. Salty foods such as soup can help to replace salt lost from your system. You may find that having small meals more frequently rather than large meals less often helps while you recover.
It's very important to stay hydrated. If your gastroenteritis is mild, drinks such as water and squash should be enough – don't drink fizzy or caffeinated drinks. If you have a more severe infection, use an oral rehydration solution (eg Dioralyte). The rehydration solution contains a powder with the right balance of sugars and salts for your body – you make it up into a solution by adding water. Always read the patient information leaflet that comes with the solution.
Some children develop short-term lactose intolerance after having gastroenteritis because the lining of the bowel is damaged and can’t digest lactose, which is a sugar found in milk and dairy products. This usually improves after about two weeks, but it’s important not to give children dairy products during this time.
Certain types of probiotics (foods containing live, beneficial bacteria) may help to reduce the duration of diarrhoea.
If you have any concerns or questions about gastroenteritis, talk to your pharmacist or GP.
I have heard dehydration is a risk in children with gastroenteritis but how will I know if my child is dehydrated?
The main risk of gastroenteritis in children is that they may become dehydrated. There are a number of symptoms of dehydration. If your child has these symptoms, you must seek medical help.
In babies and young children, gastroenteritis can be more dangerous because they become dehydrated more easily. This can occur quickly in babies because they are very small. Babies don’t need to lose much fluid to lose a significant amount of their total body fluid. Symptoms of dehydration in children include:
- lack of energy or sleepiness
- being irritable
- getting more unwell
- loss of skin elasticity – when gently pinched, the skin doesn't immediately spring back into position
- dry lips and mouth
- sunken eyes
- fewer tears than usual when crying
- fewer wet nappies than usual
- pale or patchy (mottled) skin
- fast heart rate
- rapid, shallow breathing
- cold fingers and toes – when gently squeezed, blood (pinkness of fingers and toes) takes a long time to return
Contact your GP if you think your child is becoming dehydrated, or if there is a possibility that his or her illness isn't a gut infection.
What are probiotics and how can they help if I have gastroenteritis?
Probiotics are a type of ‘good’ bacteria found in certain foods and food supplements. Certain types can be helpful in restoring the balance of bacteria in your gut after a bout of gastroenteritis. They are safe for children.
Bacteria are often thought of as harmful and a cause of illness, but there are many bacteria that live in and on your body, especially in your gut (stomach and bowels) that help to keep you healthy. Good bacteria in your gut prevent harmful organisms from growing there or entering your body through your bowel.
Gastroenteritis is a condition that results from an infection in your gut caused by harmful bacteria, viruses or parasites. They damage the cells lining the inner surface of your gut interfering with its normal processes and upsetting the balance of bacteria. Probiotic bacteria such as Lactobacillus help to restore the balance of good bacteria in your gut. This can relieve symptoms of diarrhoea and speed up your recovery. Some probiotics also help to stimulate your immune system so it can fight infections.
Probiotics are found in some yoghurts and milk drinks, but it’s important to remember that not all types of probiotics are helpful for reducing symptoms of gastroenteritis. See your GP for more information and advice before taking probiotics, particularly if you have a condition that means your immune system may be weakened (for example, HIV/AIDS). Always read the patient information leaflet that comes with your supplements.
It’s possible that certain types of probiotics may be useful for reducing some symptoms of irritable bowel syndrome (IBS). However, more research is needed.
Why are people who take antibiotics more prone to getting gastroenteritis?
Some antibiotics can upset the balance of good bacteria in your gut allowing harmful bacteria to thrive and cause diarrhoea. This is often referred to as antibiotic-associated diarrhoea.
Antibiotics are medicines prescribed to treat infections. They are used to kill or prevent the growth of harmful bacteria in your body. However, some antibiotics, such as ampicillin, clindamycin and cephalosporins, will also kill the normal bacteria in your gut. This can allow other bacteria such as Clostridium difficile (C. difficile) to grow and thrive in your gut. As this bacterium multiplies, it produces a toxin that causes diarrhoea.
It's not clear how many people get diarrhoea as a result of taking antibiotics. It has been estimated that it could be as many as one in four people, although the number may be much lower.
Most people who get antibiotic-associated diarrhoea have mild symptoms that go quickly. If you have symptoms, see your GP before you stop taking the course of antibiotics. If possible, he or she will take you off the antibiotic and prescribe a different type.
While you have symptoms, continue with your usual diet, but leave out fatty or sugary food and drinks. Make sure you drink enough fluids. If you have become dehydrated, you can take oral rehydration salts (eg Dioralyte). As long as C.difficile infection has been ruled out, taking certain probiotic supplements or yoghurt drinks may be helpful in easing symptoms of diarrhoea – however, not all probiotics are effective for this. Very occasionally, a C. difficile infection in your gut can develop into a serious disease and symptoms can be severe. If your diarrhoea doesn't improve and you're in a lot of discomfort, see your GP. He or she may take a faeces sample and blood test for analysis before referring you for treatment.
It’s possible that taking certain probiotics may help to protect against antibiotic-associated diarrhoea. However, more research is needed to find out which type of probiotic is most effective for this.
If you have any questions about antibiotics or gastroenteritis, ask your pharmacist or GP.
- Overview of gastroenteritis. The Merck Manuals. www.merckmanuals.com, published 2007
- Gastroenteritis. Prodigy. www.prodigy.clarity.co.uk, published September 2009
- Diarrhoea – antibiotic associated. Prodigy. www.prodigy.clarity.co.uk, published September 2009
- Diarrhoea and vomiting in children under 5. National Institute for Health and Clinical Excellence (NICE), 2009. www.nice.org.uk
- Gastrointestinal disease. Health Protection Agency. www.hpa.org.uk, accessed 16 May 2012
- Allen SJ, Martinez EG, Gregorio GV, et al. Probiotics for treating acute infectious diarrhoea. Cochrane Database of Systematic Reviews 2010. doi:10.1002/14651858.CD003048.pub3
- Bacterial gastroenteritis. eMedicine. www.emedicine.medscape.com, published April 2012
- Joint Formulary Committee, British National Formulary. 63rd ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2012
- Gastrointestinal disorders. The Merck Manuals. www.merckmanuals.com, published 2007
- Probiotics and diet. The British Dietetic Association. www.bda.uk.com, published January 2012
- Pediatric gastroenteritis. eMedicine. www.emedicine.medscape.com, published April 2010
- Basics for handling food safely. USDA Food Safety and Inspection Service. www.fsis.usda.gov, published June 2011
- Cleanliness helps prevent foodborne illness. USDA Food Safety and Inspection Service. www.fsis.usda.gov, published 22 March 2011
- Travellers’ diarrhoea. National Travel Health Network and Centre. www.nathnac.org, published November 2011
- Food and water hygiene. National Travel Health Network and Centre. www.nathnac.org, published January 2011
- Viral gastroenteritis. Centers for Disease Control and Prevention. www.cdc.gov, published February 2011
- Giardia infection. PubMed Health. www.ncbi.nlm.nih.gov, published May 2012
- LeWine, H. Probiotics may help prevent diarrhea due to antibiotic use. Harvard Health Blog 2012. www.health.harvard.edu
- Lactose intolerance. Better Health Channel. www.betterhealth.vic.gov.au, published October 2011
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