Gastric flu - Treating gastroenteritis in adults

Most cases of gastroenteritis do not require treatment and the symptoms will improve in a few days, although medication may be recommended if the condition is severe.

Looking after yourself

It's important to drink plenty of fluids to avoid dehydration, so you should try to make sure you have small and frequent sips of water. Fruit juice and soup can also help avoid dehydration in adults with gastroenteritis.

If you are more vulnerable to the effects of dehydration – for example, if you are elderly or have an underlying health condition – oral rehydration solutions may be recommended in addition to drinking plenty of fluids.

These solutions usually come in sachets and are available without a prescription from your local pharmacist. You dissolve them in water to make a drink that helps replace salt, glucose and other important minerals that your body loses if you are dehydrated.

If you think you may be at risk of dehydration, speak to your GP or pharmacist about whether oral rehydration solutions are suitable for you.

If you feel like eating, try to maintain a normal, healthy diet. You will be able to tolerate light, plain foods, such as rice or wholemeal bread, better than fatty, sugary, spicy or rich foods. It may be better to eat six light meals a day rather than three large meals.

You should stay away from work until you have had no symptoms for at least 48 hours to reduce the risk of spreading the infection to others.

Medication

If your symptoms are particularly severe, your GP may recommend some of the medications described below.

Antidiarrhoeal medications

Antidiarrhoeal medications are sometimes used to reduce diarrhoea. 

Loperamide is a widely used antidiarrhoeal medication for treating gastroenteritis. It slows down the movement of your bowel contents and also increases water absorption from the gut.

Constipation and dizziness are two common side effects of loperamide. Rarer side effects include stomach cramps, drowsiness, rashes and bloating.

Loperamide is not suitable for people with ulcerative colitis or dysentery (where you have diarrhoea containing blood or mucus and a fever) and shouldn't be used if you are pregnant. However, it can be used safely while breastfeeding.

Antidiarrhoeal medication should not be used by children under the age of 12 unless directly instructed by your GP.

Anti-emetic medications 

Anti-emetic medications, such as metoclopramide, are sometimes used to help prevent or reduce vomiting.

Metoclopramide can be given as tablets or an injection. It helps relax the muscles used during vomiting while also speeding up the absorption of fluids and foods by the digestive system.

Antibiotics

Antibiotics are not usually recommended for treating gastroenteritis because many cases are caused by viruses rather than bacteria. Even when bacteria is responsible, antibiotics have often been found to be no more effective than simply waiting for the symptoms to pass.

However, antibiotics may be recommended if you have particularly severe gastroenteritis and a specific bacterium has been identified in a stool sample.

Side effects of using antibiotics to treat gastroenteritis include a metallic taste in your mouth, feeling sick and vomiting.

Hospital treatment

Hospital treatment may be required for people with serious dehydration caused by gastroenteritis.

For example, admission to hospital may be recommended if:

• repeated episodes of vomiting mean that you are unable to keep down any fluids
• you have symptoms that suggest severe dehydration, such as not passing any urine
• you have an underlying medical condition, such as Crohn's disease or HIV, that means you are at an increased risk of developing serious problems

Treatment in hospital will involve administering fluids and nutrients directly into a vein (intravenously).