Diarrhoea can be acute (sudden onset and lasts less than four weeks) or chronic (persistent). This page deals with acute diarrhoea, which is common. In most cases, diarrhoea eases and goes within several days, but sometimes takes longer. The main risk is dehydration. The main treatment is to have lots to drink which aims to avoid dehydration. You should also eat as normally as possible. See a doctor if you suspect that you are dehydrating, or if you have any worrying symptoms such as those which are listed below.
What causes acute diarrhoea?
The rest of this leaflet deals only with infectious causes of acute diarrhoea. There are also other leaflets that give more details about some of the different microbes (germs) that cause infectious diarrhoea.
What are the symptoms of acute infectious diarrhoea?
If vomiting occurs, it often lasts only a day or so, but sometimes longer. Diarrhoea often continues after the vomiting stops and commonly lasts for several days or more. Slightly loose stools may persist for a week or so further before a normal pattern returns. Sometimes the symptoms last longer.
Symptoms of dehydration
Diarrhoea and vomiting may cause dehydration (a lack of fluid in the body). Consult a doctor quickly if you suspect you are becoming dehydrated. Mild dehydration is common and is usually easily and quickly reversed by drinking lots of fluids. Severe dehydration can be fatal unless quickly treated. This is because the organs of your body need a certain amount of fluid to function.
Dehydration in adults with acute diarrhoea is more likely to occur in:
Do I need any tests?
Most people with acute infectious diarrhoea do not need to see a doctor or seek medical advice. Symptoms are often quite mild and commonly get better within a few days without any medical treatment.
However, in some circumstances, you may need to see a doctor (see below about when to seek medical advice). The doctor may ask you various questions. For example: about recent travel abroad, if you have been in contact with someone with similar symptoms, if you have recently taken antibiotics, or been admitted to hospital. This is to look for possible causes of your diarrhoea. The doctor will also usually examine you, especially looking for signs of dehydration.
Tests are not usually needed. However, if you are particularly unwell, have bloody stools, have recently travelled abroad, are admitted to hospital, or your symptoms are not getting better, then your doctor may ask you to collect a stool sample. This can then be examined in the laboratory to look for the cause of the infection.
When should I seek medical advice?
Seek medical advice in any of the following situations, or if any other symptoms occur that you are concerned about:
What is the treatment for infectious diarrhoea in adults?
Symptoms often settle within a few days or so as your immune system usually clears the infection. Occasionally, admission to hospital is needed if symptoms are severe, or if complications develop (see below).
The following are commonly advised until symptoms ease.
Fluids - have lots to drink
The aim is to prevent dehydration, or to treat dehydration if it has developed. (Note: if you suspect that you are dehydrated, you should contact a doctor.)
For most adults, fluids drunk to keep hydrated should mainly be water. But, ideally, include some soup. It is best not to have drinks that contain a lot of sugar, such as cola or pop, as they can sometimes make diarrhoea worse.
Rehydration drinks are recommended for people who are frail, or over the age of 60, or who have underlying health problems. They are made from sachets that you can buy from pharmacies. (The sachets are also available on prescription.) You add the contents of the sachet to water. Rehydration drinks provide a good balance of water, salts, and sugar. They do not stop or reduce diarrhoea. However, the small amount of sugar and salt helps the water to be absorbed better from the gut into the body. Do not use home-made salt/sugar drinks, as the quantity of salt and sugar has to be exact.
Anti-secretory medicines are designed to be used with rehydration treatment. They reduce the amount of water that is released into the gut during an episode of diarrhoea. They can be used for children who are older than 3 months of age and adults.
Eat as normally as possible
It used to be advised to not eat for a while if you had infectious diarrhoea. However, now it is advised to eat small, light meals if you can. Be guided by your appetite. You may not feel like food and most adults can do without food for a few days. Eat as soon as you are able - but don't stop drinking. If you do feel like eating, avoid fatty, spicy or heavy food at first. Plain foods such as wholemeal bread and rice are good foods to try eating first.
Antidiarrhoeal medicines are not usually necessary. However, you may wish to reduce the number of trips that you need to make to the toilet. You can buy antidiarrhoeal medicines from pharmacies. The safest and most effective is loperamide. The adult dose of this is two capsules at first. This is followed by one capsule after each time you pass some diarrhoea, up to a maximum of eight capsules in 24 hours. It works by slowing down your gut's activity. You should not take loperamide for longer than five days.
Note: do not give antidiarrhoeal medicines to children aged under 12 years. Also, do not use antidiarrhoeal medicines if you pass blood or mucus with the diarrhoea or if you have a high temperature. People with certain conditions should not take loperamide. Therefore, read the leaflet that comes with the medicine to be safe. For example, pregnant women should not take loperamide.
Paracetamol or ibuprofen are useful to ease a high temperature or headache.
As explained above, if symptoms are severe, or persist more than several days, your doctor may ask for a sample of the diarrhoea. This is sent to the laboratory to look for infecting germs (bacteria, parasites, etc). Sometimes an antibiotic or other treatments are needed if certain bacteria or other infections are found to be the cause. Antibiotics are of no use for infectious diarrhoea caused by viruses, and may even make things worse.
Are there any complications that may occur?
Complications are uncommon in the UK. They are more likely in the very young, in pregnant women, or in the elderly. They are also more likely if you have a chronic (ongoing) disease such as diabetes, or if your immune system may not be working fully. For example, if you are taking long-term steroid medication or you are having chemotherapy treatment for cancer.
Possible complications include the following:
Preventing spread of infection to others
Some infections causing diarrhoea are very easily passed on from person to person. If you have acute diarrhoea, the following are also recommended to prevent the spread of infection to others:
Can infectious diarrhoea be prevented?
The advice given in the previous section is mainly aimed at preventing the spread of infection to other people. However, even when we are not in contact with someone with infectious diarrhoea, proper storage, preparation and cooking of food, and good hygiene help to prevent it.
In particular, always wash your hands:
The simple measure of washing hands regularly and properly is known to make a big difference to the chance of developing infectious diarrhoea.
You should also take extra measures when in countries of poor sanitation. For example, avoid water and other drinks that may not be safe, and avoid food washed in unsafe water.