Diarrhea is where you frequently pass watery or loose poo. Some people may also have other symptoms, depending on the cause. It affects most people from time to time and is usually nothing to worry about. However, it can be distressing and unpleasant until it passes, which normally takes a few days to a week. The excessive loss of water in your poo can also sometimes lead to symptoms of dehydration, which can be serious if it’s not recognised and treated quickly.

When to seek medical advice

Babies

• You should contact the doctor if your baby has had six or more episodes of diarrhea in the past 24 hours, or if they’ve vomited three times or more in the past 24 hours.
• You should also seek advice if your baby has any symptoms of dehydration.

Children

Had six or more episodes of diarrhea in the past 24 hours diarrhea and vomiting at the same time, watery poo, blood in their poo, a severe or continuous stomach ache symptoms of dehydration.

Adults

• There’s blood in your poo.
• You’re vomiting persistently.
• You’ve lost a lot of weight.
• You’ve passed a large amount of very watery diarrhea.
• It occurs at night and is disturbing your sleep.
• You’ve recently taken antibiotics or been treated in hospital.
• You have symptoms of dehydration.
• Your poo is dark or black – this may be a sign of bleeding inside your stomach.
• You should also contact your GP if you have persistent diarrhea. Most cases in adults will pass in two to four days.

Causes of diarrhea

There are many different causes of diarrhea, but a bowel infection (gastroenteritis) is a common cause in both adults and children. Gastroenteritis can be caused by:

• A virus – such as norovirus or rotavirus
• Bacteria – such as campylobacter or Escherichia coli (E. coli), which are often picked up from contaminated food.
• A parasite – such as a parasite that causes giardiasis, which is spread in contaminated water. These infections can sometimes be caught during travel abroad, particularly to areas with poor standards of public hygiene. This is known as travelers’ diarrhea.

Diarrhea can also be the result of:

• Anxiety
• A food allergy
• Medication
• A long-term condition, such as irritable bowel syndrome (IBS)

Treating diarrhea

Most cases of diarrhea clear up after a few days without treatment.
However, diarrhea can lead to dehydration, so you should drink plenty of fluids until it passes. It’s very important that babies and small children don’t become dehydrated. Your pharmacist may suggest you use an oral rehydration solution (ORS) if you or your child are particularly at risk of dehydration.

You should eat solid food as soon as you feel able to. If you’re breastfeeding or bottle feeding your baby and they have diarrhea, you should try to feed them as normal. Stay at home until at least 48 hours after the last episode of diarrhea to prevent spreading any infection to others.

Medications to reduce diarrhea, such as loperamide, are available. However, these aren’t usually necessary, and most types shouldn’t be given to children.

Preventing diarrhea

Diarrhea is often caused by an infection. You can reduce your risk by making sure you maintain high standards of hygiene.
For example, you should:

• Wash your hands thoroughly with soap and warm water after going to the toilet and before eating or preparing food. Clean the toilet, including the handle and the seat, with disinfectant after each bout of diarrhea.
• Avoid sharing towels, flannels, cutlery or utensils with others.
• Wash soiled clothing and bed linen separately from other clothes and at the highest temperature possible – for example, 60C or higher for linen – after first removing any poo into the toilet avoid returning to work or school until at least 48 hours after the last episode of diarrhea.

Traveler’s diarrhea

It’s important to practice good food and water hygiene while traveling abroad, such as avoiding potentially unsafe tap water and undercooked food. If you’re planning a trip abroad, check health advice for the countries you’ll be travelling to.

Rotavirus vaccination
Rotavirus is a virus that commonly causes diarrhea in children. A vaccine that helps protect children against rotavirus is now part of the routine childhood vaccination schedule. This vaccine is given as a liquid that’s dropped into a baby’s mouth. It’s given in two doses, with the first given at two months and another at three months.