Digestive
Diarrhoea
Passing looser or more frequent stools than normal, usually settling within a few days.
Education and reference only. This explains the common causes of diarrhoea and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is diarrhoea?
Diarrhoea means passing loose or watery poo more often than usual. Most cases are short-lived and caused by a tummy bug, settling on their own within a few days to a week.
- Get urgent help: Blood in the stool, or black, tarry stools. Signs of dehydration such as dizziness, passing very little urine, or sunken eyes.
- Self-care: For a short bout of diarrhoea the most important thing is to keep sipping fluids so you do not become dehydrated, taking small, frequent drinks if you feel sick.
About diarrhoea
Diarrhoea means passing loose or watery poo more often than usual. Most cases are short-lived and caused by a tummy bug, settling on their own within a few days to a week. The main risk during an episode is becoming dehydrated, especially in young children, older people and anyone with another illness. Diarrhoea that keeps coming back, lasts a long time, or comes with blood, weight loss or severe pain is more likely to point to an ongoing bowel condition and is worth getting checked. Thinking about how long it has lasted, what it looks like, and any travel, food or medicine that came before it can help you and a clinician work out the likely cause.
When to get help
Call 999 or go to A&E if diarrhoea comes with any of these warning signs:
- Blood in the stool, or black, tarry stools.
- Signs of dehydration such as dizziness, passing very little urine, or sunken eyes.
- Diarrhoea lasting more than about a week, or with severe tummy pain or a high temperature.
- Recent foreign travel or recent antibiotics together with severe symptoms.
When to see a doctor
See a doctor if your diarrhoea has not started to settle after about a week, keeps coming back, or regularly disturbs your sleep. It is also worth getting checked if you have lost weight without trying, are bringing up blood or mucus, or have a family history of bowel disease. Anyone with a long-term condition such as diabetes, or who is frail, pregnant or has a weakened immune system, should seek advice sooner, as should parents whose child has frequent diarrhoea or seems unwell.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of diarrhoea
Diarrhoea has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
For a short bout of diarrhoea the most important thing is to keep sipping fluids so you do not become dehydrated, taking small, frequent drinks if you feel sick. Oral rehydration sachets from a pharmacy can help replace lost salts and water, particularly for the very young or older people. Eat when you feel able, choosing plain foods you fancy rather than forcing anything, and rest until you feel better. Wash your hands well with soap and water after using the toilet and before handling food, and stay off work or school until you have been free of diarrhoea for a couple of days to avoid passing on a bug.
Answers
Diarrhoea: frequently asked questions
How long should diarrhoea normally last?
Most short-lived diarrhoea from a tummy bug improves within two or three days and clears up within about a week. If it carries on beyond that, keeps returning, or comes with blood or weight loss, it is worth getting checked rather than waiting it out.
What is the most important thing to do when I have diarrhoea?
Keep drinking fluids in small, frequent sips so you do not become dehydrated. Oral rehydration sachets from a pharmacy help replace lost salts and water, and you should eat plain foods when you feel able.
When does diarrhoea become an emergency?
Seek urgent help if you notice blood or black, tarry stools, signs of dehydration such as dizziness and passing very little urine, or severe tummy pain with a high temperature. These need prompt assessment rather than home care.
Should I take anti-diarrhoea medicine?
For a simple short-lived bout, fluids and rest are usually enough. A pharmacist can advise whether an anti-diarrhoea treatment is suitable for you, but it should be avoided if there is blood in the stool or a high temperature, so ask before using one.
Sources
Where this is drawn from
- NICE CKS: Diarrhoea – adult's assessment.
- Guts UK charity.
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