Occasional bouts of diarrhoea (diarrhea) are a fact of life – we have all experienced them. This section is for teenagers and adults with sudden-onset diarrhoea that lasts for less than 4 weeks. Diarrhoea in a child, especially in a baby, can be serious so your doctor should be consulted.

What You Can Do to Help Yourself

Treat with loperamide. A mild attack of diarrhoea can usually be stopped by taking loperamide, which you can buy from any pharmacy. Read the instructions carefully and do not exceed the recommended dose. Do not take loperamide if you have blood in your poo – instead, see your doctor (see below).

Increase your fluid intake. It is important not to become dehydrated, so keep up your fluid intake with fruit juices and soups. If you have a lot of diarrhoea it might be a good idea to take a solution of oral rehydration salts. This is because when you have diarrhoea you lose salts (particularly potassium) as well as water, and rehydration products can make up the salts you have lost. You can buy oral rehydration salts from pharmacies; ask your pharmacist for advice.

Take probiotic drinks or yoghurts. Probiotics (‘friendly’ bacteria) can help. They will not cure the diarrhoea but will shorten the duration of illness by an average of about 25 hours. Another study states that stool transit time can be reduced by 12.4 hours. You can buy probiotic drinks and yoghurts from supermarkets, and as supplements from pharmacies and health food stores. Lactobacillus casei (in Actimel and Yakult) and Saccharomyces boulardii (in Optibac) are the commonest.

Think about your contraceptive method. Be aware that severe diarrhoea can make the oral contraceptive pill less effective and use extra precautions.

When You Should See Your Doctor

  • If you have had diarrhoea for more than 48 hours.
  • If there is blood or pus mixed in with the diarrhoea.
  • If you have a temperature (fever).
  • If you are feeling very unwell.
  • If the diarrhoea is extremely profuse.
  • When you have another illness (such as diabetes) and/or you are taking medication. If you have severe diarrhoea your medication may not be absorbed properly and some medications (e.g. for Parkinson’s disease) need to be finely tuned.
  • If you have recently been to a developing country. You need to tell your doctor where you have been in case you have picked up an unusual infection that needs special investigation.

Causes of Short-Term Diarrhoea

A virus is the usual cause, especially norovirus. Norovirus is easy to catch, because very few actual virus particles are needed to cause an infection. It usually comes on suddenly with vomiting and tummy cramps, as well as watery diarrhoea. Some people have headache and muscle pains. Fortunately, it is usually over after 24-72 hours of misery. Infection comes from the poo of people with the virus. If it gets onto their hands, they can then spread the virus by touching things that others will touch. To reduce your chances of catching norovirus, wash your hands thoroughly before eating anything, and wash raw fruit well as it could have been handled by someone with the virus. It is also a good idea to wear gloves on public transport if there is a lot of norovirus about.

‘Food poisoning’ can mean eating something that disagrees with you (such as a very spicy meal if you are not used to spices), but it can also mean infection with various bacteria from the food. Crabs and shell-fish are well-known sources, as is under-cooked meat or reheated rice. Thinking about what you have eaten over the past 48 hours may pin-point the problem. Food poisoning usually causes vomiting, but diarrhoea may follow. Tummy pain is common.

Giardia (pronounced gee-ard-ee-a) is a tiny parasite that can cause chronic, long-term diarrhoea, but it also can cause short bouts of diarrhoea, often with bloating and weight loss. It is common in tropical countries but occurs worldwide.

What to Do If the Diarrhoea Doesn’t Go Away Completely

If you have chronic (persistent) diarrhoea that lasts for more than 4 weeks, see your doctor for advice as it may be a sign of a more serious illness, or a condition like irritable bowel syndrome.


First published on: embarrassingproblems.com
Reviewed and edited by: Dr Kevin Barrett
Last updated: October 2020

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