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Acute diarrhoea in children

Diarrhoea can be of sudden onset and lasting for less than two weeks (acute) or persistent (chronic). This leaflet deals with infectious diarrhoea, which is common in children. In most cases, diarrhoea improves and stops within several days but can sometimes takes longer. The main risk is lack of fluid in the body (dehydration). The main treatment is to give the affected child enough to drink; this may be by giving special rehydration drinks. Medical help should be sought if there is suspicion that the child is dehydrating, or if they have any worrying symptoms such as those listed below.

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What causes acute diarrhoea in children?

Infection of the gut (gastroenteritis)

An infection of the gut is the most common cause and includes:

  • A virus is by far the commonest cause of infective diarrhoea in the UK. Usually it is just 'one of those germs going about'. Viruses are easily spread from person to person by close contact or when an infected person prepares food for others. Infection with a virus called rotavirus is the most common cause of diarrhoea in children in the UK although there has been a significant reduction in cases since the introduction of the rotavirus vaccine for all UK children in 2013. Adenoviruses and norovirus are other common viruses causing diarrhoeal illnesses.

  • Food poisoning (eating food infected with bacteria ) causes some cases of diarrhoea. The most common examples are species of bacteria called Campylobacter, Salmonella and Escherichia coli (usually shortened to E. coli). Food infected with parasites can cause food poisoning but this is less common in the UK.

  • Water which is contaminated by bacteria or other germs is another common cause of infective diarrhoea across the world but is rare in the UK and most common in countries with poor sanitation.

Non-infectious causes

Non-infectious causes of sudden-onset (acute) diarrhoea are uncommon in children - these include inflammation of the gut (colitis), food intolerances or allergies such as coeliac disease, and various rare disorders of the gut. Toddler's diarrhoea is a common cause of persistent (chronic) diarrhoea in young children.

The rest of this leaflet deals only with infectious causes of acute diarrhoea. Click the links to the various other leaflets that give more details about some of the different microbes that cause infectious diarrhoea.

What are the symptoms of acute diarrhoea in children?

Most diarrhoeal illnesses in children start with vomiting which usually settles within 24-48 hours. Symptoms can range from a mild stomach upset for a day or two with slight diarrhoea, to severe watery diarrhoea for several days or longer. Diarrhoea means loose or watery stools (faeces), usually at least three times in 24 hours.

Common symptoms of acute diarrhoea in children are:

Diarrhoea often lasts for 3-5 days, sometimes longer. It often continues for a few days after any vomiting stops. Slightly loose stools may continue (persist) for a week or so further before a normal pattern returns and can occasionally persist longer than this. Some children develop a temporary "lactose intolerance" after an acute diarrhoeal illness where they get loose stools after drinking milk or eating dairy products. This settles with time.

Symptoms of lack of fluid in the body (dehydration)

Diarrhoea and vomiting may cause dehydration. Mild dehydration is common and is usually easily and quickly reversed by drinking fluids. Severe dehydration can be very serious (occasionally fatal) unless quickly treated because the organs of the body need a certain amount of fluid to function normally.

  • Symptoms of dehydration in children include:

    • Passing little urine.

    • A dry mouth.

    • A dry tongue and lips.

    • Fewer tears when crying.

    • Sunken eyes.

    • Weakness.

    • Being irritable or lacking in energy (lethargic).

  • Symptoms of severe dehydration in children include:

    • Drowsiness.

    • Pale or mottled skin.

    • Cold hands or feet.

    • Very few wet nappies.

    • Fast (but often shallow) breathing.

Note: severe dehydration is a medical emergency and immediate medical attention is needed.

Dehydration in children with sudden-onset (acute) diarrhoea is more likely to occur in:

  • Babies under the age of 1 year and particularly those under 6 months old. This is because babies need to lose less fluid to lose a significant proportion of their total body fluid.

  • Babies under the age of 1 year who were a low birth weight and who have not caught up to their expected weight

  • A breastfed baby who has stopped breastfeeding during their illness.

  • Any baby or child who has does not drunk much during the infection of the gut (gastroenteritis).

  • Any baby or child with severe diarrhoea and being sick (vomiting), especially if they have passed six or more diarrhoeal stools and/or vomited three or more times in the previous 24 hours

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Does my child need any tests for acute diarrhoea?

For most children, diarrhoea will usually be quite mild and will get better within a few days without any treatment other than drinking regular fluids.

However, in some circumstances, medical advice may be needed if the child is particularly unwell or showing signs of dehydration. In this case the child will be examined for signs of dehydration (eg, checking heart rate) and their abdomen will be examined to check for tenderness.

Tests are not usually needed. A stool sample can be helpful if the symptoms have developed after recent travel abroad, if the symptoms have persisted for a week (this makes food poisoning more likely) or if the child is unwell enough to be admitted to hospital.

The stool sample will then be examined in the laboratory to see if there is a bacterial cause of the infection.

When should I seek medical advice?

As mentioned already, most children with diarrhoea have mild symptoms which get better in a few days. The important thing is to ensure that they are drinking well. In most cases, medical advice is not needed. However, medical advice should be sought in the following situations:

  • If the child is under the age of 6 months and has multiple episodes of diarrhoea or they persist for more than 24 hours.

  • If the child has an underlying medical condition - for example, heart or kidney problems or diabetes.

  • If the child appears to be becoming dehydrated.

  • If the child appears drowsy or confused.

  • If the child is being sick (vomiting) and unable to keep fluids down.

  • If there is blood in their diarrhoea or vomit.

  • If the child has severe tummy (abdominal) pain.

  • If the child has severe symptoms or if their condition is getting worse rather than improving.

  • If the child's symptoms are not settling (for example, vomiting for more than two days, or diarrhoea that does not start to improve after four days).

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What is the treatment for diarrhoea in children?

Diarrhoea usually settles within a few days or so as the child's immune system is usually able to clear the infection. Children can usually be treated at home. Occasionally, admission to hospital is needed if symptoms are severe, or if complications develop.

Fluids to prevent lack of fluid in the body (dehydration)

You should encourage your child to drink fluids. The aim is to prevent dehydration. The fluids lost if they have been sick (vomited) and/or have had diarrhoea need to be replaced.

If the child is still vomiting then large quantities of fluid will often make this worse. The child should be encouraged to drink small volumes of fluid very frequently. This can be via a syringe and should be 5-10 ml of fluid every five minutes. Once the vomiting has stopped they can be encouraged to drink in the normal way but with more fluids than normal. The child should continue with their normal diet once the vomiting has settled. . but fruit juices and fizzy drinks should be avoided as they can make diarrhoea worse.

In babies under 6 months of age, breastfeeds or bottle-feeds should be encouraged as normal. - some babies will drink more than normal.

Rehydration drinks may be advised by a doctor for children at increased risk of dehydration or who have signs of mild dehydration. These are made from sachets available from pharmacies. Rehydration drinks provide a perfect balance of water, salts and sugar. The small amount of sugar and salt helps the water to be taken in (absorbed) better from the gut into the body.

Home-made salt/sugar mixtures are sometimes used in developing countries if rehydration drinks are not available but they have to be made carefully, as too much salt can be dangerous to a child. Rehydration drinks are cheap and readily available in the UK and are the best treatment for your child.

Note: if you suspect that your child is dehydrated, or is becoming dehydrated, you should seek medical advice urgently.

Fluids to treat dehydration

If your child is mildly dehydrated, this may be treated by giving them rehydration drinks. The amount given depends on the age and the weight of the child and it is very important to follow the instructions carefully. If rehydration drinks are not available for whatever reason, other fluids such as water or dilute squash should be given. Breastfeeding should be continued as normal. Fluid intake is more important than food intake

Sometimes a child may need to be admitted to hospital for treatment if they are dehydrated. Treatment in hospital usually involves giving rehydration solution via a special tube called a nasogastric tube. This tube passes through the child's nose, down their throat and directly into their stomach. An alternative treatment is with fluids given directly into a vein (intravenous fluids).

Eat as normally as possible once any dehydration has been treated

Correcting any dehydration is the first priority. However, if the child is not dehydrated (most cases), or once any dehydration has been corrected and the vomiting has settled, a normal diet should be encouraged. So:

  • Breastfed babies should continue to be breastfed if they will take it. This will usually be in addition to extra rehydration drinks (described above).

  • Bottle-fed babies should be fed with their normal full-strength feeds if they will take it. Again, this will usually be in addition to extra rehydration drinks (described above).

  • Older children - should be offered food every now and then. However, if they do not want to eat, that is fine. Drinks are the most important and food can wait until their appetite returns.

Medication is not usually needed

Medicines should not normally be given to stop diarrhoea to children under 12 years old. They are unsafe to give to children, due to possible serious complications. However, paracetamol or ibuprofen can be given to ease any high temperature (fever) or headache. See the separate leaflet called Diarrhoea Medicine for further information.

If symptoms are severe or have persisted for more than a few days, and a stool sample has been requested, this will be sent to the laboratory for testing. If a bacterial cause is found and the diarrhoea is still ongoing, then antibiotics will be prescribed. Antibiotics should never be given without confirmation of the cause of the infection.

Complications of diarrhoea in children

Complications from infective diarrhoea in children are uncommon in the UK but are more likely in very young children or those with an ongoing (chronic) disease such as diabetes or if their immune system is weakened - for example, if they are taking long-term steroid medication or they are having chemotherapy treatment for cancer.

Possible complications include the following:

  • Lack of fluid (dehydration) and salt (electrolyte) imbalance in the body/dehydration. This is the most common complication. It occurs if the water and salts that are lost in the child's diarrhoea or vomit are not replaced by their drinking enough fluids. If the child drinks well, then it is unlikely to occur, or is only likely to be mild and will soon recover once the child starts drinking better.

  • Reactive complications. Rarely, other parts of the body can react to an infection that occurs in the gut. This can cause symptoms such as skin inflammation, eye inflammation (either conjunctivitis or uveitis) or joint inflammation (arthritis). Reactive complications are uncommon.

  • Spread of infection to other parts of your child's body, such as their bones, joints, or the meninges that surround their brain and spinal cord. This is rare. If it does occur, it is more likely if the diarrhoea is caused by Salmonella spp. infection.

  • Persistent diarrhoea syndromes may (rarely) develop.

  • Irritable bowel syndrome symptoms are sometimes triggered by a bout of infectious diarrhoea.

  • Lactose intolerance can sometimes occur for a period of time after infectious diarrhoea. It is known as secondary or acquired lactose intolerance. The child's gut lining can be damaged by the episode of diarrhoea which leads to lack of a chemical (enzyme) called lactase that is needed to help the body digest a sugar called lactose that is in milk. Lactose intolerance leads to bloating, tummy (abdominal) pain, wind and watery stools after drinking milk. The condition gets better when the infection is over and the gut lining heals.

  • Haemolytic uraemic syndrome is a rare but serious complication, usually associated with diarrhoea caused by a certain type of E. coli infection - E. coli O157. It causes anaemia, a low platelet count in the blood and kidney failure. If recognised and treated, most children recover well.

  • Malnutrition may follow some gut infections. This is mainly a risk for children in developing countries.

Preventing spread of infection to others

Diarrhoeal infections can very easily be passed on from person to person. Therefore, measures should be taken to try to reduce this chance.

If your baby has diarrhoea, be especially careful to wash your hands after changing nappies and before preparing, serving, or eating food. Ideally, use liquid soap in warm running water but any soap is better than none. Dry your hands properly after washing.

For older children, whilst they have diarrhoea, the following are recommended:

  • Regularly clean the toilets used, with disinfectant. Also, clean the flush handle, toilet seat, sink taps, bathroom surfaces and door handles at least daily with hot water and detergent. Disposable cleaning cloths should be used (or a cloth just for toilet use).

  • If a potty has to be used, wear gloves when you handle it, dispose of the contents into a toilet, then wash the potty with hot water and detergent and leave it to dry.

  • Make sure your child washes their hands after going to the toilet. Ideally, they should use liquid soap in warm running water but any soap is better than none. Dry properly after washing.

  • If clothing or bedding is soiled, first remove any stools (faeces) into the toilet. Then wash in a separate wash at as high a temperature as possible.

  • Don't let your child share towels and flannels.

  • Don't let them help to prepare food for others.

  • They should stay off school, nursery, etc, until at least 48 hours after the last episode of diarrhoea or being sick (vomiting). Sometimes this time may be longer with certain bacterial infections - this information will be passed on by the local health protection team who deal with these infections.

  • If the cause of diarrhoea is known to be (or suspected to be) a germ called Cryptosporidium spp., the child should not swim in swimming pools for two weeks after the last episode of diarrhoea.

Can diarrhoea in children be prevented?

The advice given in the previous section is mainly aimed at preventing the spread of infection to other people. But, even when there has been no contact with someone with infectious diarrhoea, proper storage, preparation and cooking of food and good hygiene can reduce the risk of catching an infection. In particular, handwashing is an important protective mechanism, particularly:

  • After going to the toilet (and after changing nappies).

  • Before touching food. And also, between handling raw meat and food ready to be eaten. (There may be some germs (bacteria) on raw meat.)

  • After gardening.

  • After playing with pets (healthy animals can carry certain harmful bacteria).

The simple measure of washing hands regularly and properly is known to make a big difference to the chance of developing gut infections and diarrhoea.

Extra measures should be taken when travelling in countries with poor sanitation. For example, water and ice should be avoided, along with drinks made with water and food washed in unsafe water.

Breastfeeding is also protective. Breastfed babies are much less likely to develop infectious diarrhoea compared to bottle-fed babies.


As mentioned earlier, rotavirus used to be the most common cause of infective diarrhoea in children. There is an effective vaccine against rotavirus which has been offered routinely to babies in the UK since September 2013 and. This vaccine is via oral drops are given at 2 and 3 months old.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • Next review due: 21 Mar 2028
  • 23 Mar 2023 | Latest version

    Last updated by

    Dr Pippa Vincent, MRCGP

    Peer reviewed by

    Dr Hayley Willacy, FRCGP
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