Diarrhoea is passing looser or more frequent stools than is normal for you.
It affects most people from time to time and is usually nothing to worry about.
There are many different causes of diarrhoea, but a bowel infection (gastroenteritis) is a common cause in both adults and children.
Gastroenteritis can be caused by:
The symptoms associated with diarrhoea can vary depending on the cause. For example, if your diarrhoea is caused by an infection, you may also have a fever and severe stomach cramps.
In adults, bouts of diarrhoea can sometimes be the result of anxiety, or drinking too much coffee or alcohol. Diarrhoea can also be a side effect of certain types of medication.
Read more about the causes of diarrhoea.
Most cases of diarrhoea clear up after a few days without treatment.
In adults, it usually improves after 2-4 days. In children, it often lasts slightly longer, between 5-7 days.
Diarrhoea can lead to dehydration if it's severe and/or frequent so you should drink plenty of fluids (small, frequent sips of water) while you have diarrhoea. It is very important that babies and small children do not become dehydrated.
Your pharmacist may suggest you take an oral rehydration solution (ORS) if you are particularly vulnerable to the effects of dehydration. For example, if you are 60 years of age or over, frail or you have a health condition, such as cardiovascular disease.
Antidiarrhoeal medicines is not usually necessary unless it is important you shorten the length of time your diarrhoea lasts (for example, if you need to take a long-haul flight). Loperamide is the preferred medicine because it has been shown to be effective and has few side effects. Children should not take this medicine.
Read more about treating diarrhoea.
In adults, diarrhoea that lasts more than a few weeks may be a sign of a more serious condition, such as bowel cancer, Crohn's disease or irritable bowel syndrome (IBS).
If you have persistent diarrhoea, you should visit your GP so the doctor can try to establish a cause. This is particularly important if you have blood or pus in your faeces.
If your baby or child has had six or more episodes of diarrhoea in the last 24 hours, you should take them to see your GP.
You should also visit your GP if you have diarrhoea and you are very unwell. Your GP may decide to investigate further - for example, they may send a stool sample to be analysed in a laboratory.
Read more about when to contact your GP.
To prevent diarrhoea caused by infections, you should take steps to prevent the infection spreading. For example, make sure you:
Read more about preventing diarrhoea.