There are a number of causes of diarrhoea and vomiting in children and adults. The most common cause of short lived diarrhoea and vomiting of sudden onset is infection. This is either a viral illness or as a result of food poisoning. Usually, patients with gastroenteritis will settle at home without treatment. Children will also recover without treatment but need to keep up a good fluid intake to prevent dehydration.

Treatment is not usually needed

There are few germs that cause diarrhoea and vomiting that require any treatment other than fluid replacement. In children the infection is often caused by a virus; again no treatment is needed to clear the infection. It is common for children to have a few episodes of vomiting or some loose bowel motions with other infections like upper respiratory tract viruses that cause coughs and colds.

If your diarrhoea persists for more than a day or two, you can reduce the frequency of bowel motions by buying some loperamide over the counter at the chemist. Make sure that you follow the instructions regarding dosage.

Fluid replacement

Usually, fluid replacement can be given by mouth. This is only a problem if there is persistent vomiting. Vomiting, although unpleasant, if it lasts overnight or for a few hours and then settles is not usually a problem. Once the initial fluid loss is replaced, it is entirely appropriate to resume a normal diet.

Oral rehydration solutions

Suitable oral rehydration solutions are available from all chemists. These contain the correct concentrations of sugar and salt to enable the fluid to be absorbed. Plain water is not adequate if nothing else is taken by mouth. Making your own rehydration solution is dangerous because the quantity of salt or sugar must be correct. If the concentration of sugar or salt is too high more fluid will actually be drawn into the gut and dehydration made worse. Coca-Cola and similar drinks do contain sugar and salt but the concentration of sugar is too high; they are not suitable replacements in diarrhoea as they can, theoretically, make it worse.

Normal diet

There is no evidence that dietary restriction is helpful in stopping diarrhoea in the majority of patients. Intolerance to milk after diarrhoea occurs occasionally in children but is uncommon in the UK (less than 1 child in 20). Your child can resume normal feeds as soon as the vomiting has settled. If diarrhoea persists, give additional rehydration solution after each loose stool (approximately 10ml for each kilogram of weight).

Keep feeding children

Starving children through a tummy upset is of no benefit and these children will lose more weight if not fed. Many parents say that after a feed their toddler passes the food straight through into the nappy. This is not true. What appears in the nappy is partly digested food from previous meals but the body's natural reflex is to pass a bowel motion after feeding so it does seem that the food and fluid is passing straight through. If your baby is being breast fed then continuing to breast feed is important and likely to shorten the duration of diarrhoea.

When to see your doctor

If your diarrhoea contains blood you should see your doctor in case the diarrhoea is due to inflammation of the bowel (colitis) rather than infection. This is much less common than diarrhoea due to infection. We are also happy to see you in the surgery if your illness is causing a high fever and you are seriously unwell.

Occasionally, diarrhoea that is persistent and associated with crampy abdominal pain is caused by a germ called Campylobacter. If your diarrhoea is not showing any signs of settling after a week then we can send a sample to the hospital to try and identify the germ responsible. Campylobacter infections usually settle without treatment. If symptoms persist an antibiotic can help to eradicate this infection.

Adults who are involved in food handling and preparation should also have a stool sample sent to the laboratory to exclude infections like Salmonella that pose a public health risk.

Parents who are concerned that their child is dehydrating should bring him/her to the surgery for assessment. Symptoms of dehydration include cold hands and feet, dry nappies, listleness or drowsiness. The skin may be slack, the mouth dry and eyes sunken. If you are worried, bring your child to the surgery for us to check over.