Diarrhoea – How to manage it


What is diarrhoea?

The definition of diarrhoea can range from slightly loose stools to very watery stools, but it generally refers to the passing of watery or loose stools more than is considered normal for you. It can occur quite suddenly (acute) or can be a persistent issue (chronic).[1]

Diarrhoea happens when the large intestine lining is irritated or inflamed. This irritation stops salts and water from being extracted by the intestine which leads to us passing watery stools.

A healthy adult usually passes up to 300g of normal formed stool (poo) throughout the day, but passing more than 400ml of loose or watery stool in a day is abnormal.[2]

Most people will experience diarrhoea on occasion, and it is usually nothing to be concerned about. However, if it occurs on a regular basis it may be accompanied by pain and can be upsetting. (Normal diarrhoea usually passes within 5 to 7 days, but if it continues you should consult your doctor.)

Diarrhoea symptoms:

– An urge to pass loose or watery stools at least 3 times a day.

– Cramps in the stomach or abdomen.

– Bloating and flatulence (passing wind or ‘farting’).

– Nausea or vomiting.

– Loss of appetite.

– Feeling too hot or having a high temperature.

– Headaches.

– An aching body.

What causes diarrhoea?

Diarrhoea can be caused by many things, but some main factors include: infections and food poisoning; chronic conditions (such as Crohn’s disease, Irritable Bowel Syndrome (IBS); coeliac disease, lactose intolerance and ulcerative colitis); dietary changes; stress; and medication.[3]

Infections and food poisoning:

Diarrhoea can be caused by a bowel infection (generally called gastroenteritis). This can be the result of: viruses such as norovirus or rotavirus; bacteria, such as salmonella, shigella, campylobacter, E. coli, or C. difficile; or intestinal parasites, such as giardia intestinalis which is found in contaminated food and drink.

Diarrhoea caused by infection and food poisoning tends to occur suddenly and can last from 5 to 10 days. If it is accompanied by vomiting this usually goes away after the first 2 to 3 days.

Chronic conditions:

Persistent and occasional diarrhoea is very often caused by conditions such as food allergies, Crohn’s disease, ulcerative colitis, Irritable Bowel Syndrome (IBS), coeliac disease, and lactose intolerance.

Food allergies can cause diarrhoea because consuming the food which the body is allergic to triggers a response in the immune system which releases chemicals to get the body to expel the allergen from the intestine.

Conditions which cause the colon lining to become inflamed, such as in the case of Crohn’s disease and ulcerative colitis, can also lead the body to trigger an immunological reaction which tries to ‘flush out’ the intestine.

In the case of IBS, diarrhoea can happen as a result of eating too many foods high in FODMAPs, which leads to water being drawn into the small intestine to ‘flush out’ the material which cannot be absorbed.[4]

Dietary changes:

Diarrhoea can also occur as a result of making changes to your diet which can include:

– Eating a lot of rich food (often with a lot of cream or butter).

– Drinking a lot of alcohol.

– Eating too much sorbitol artificial sweetener (found in chewing gum).

– Eating a lot of fruits containing sorbitol, such as apples, pears, apricots, cherries, blackberries, plums, lychees, nectarines, avocados, peaches and prunes.[5]

Stress-related diarrhoea

Anxiety and stress can lead to people experiencing diarrhoea, particularly if they have IBS. As a result, many people find it beneficial to practice:

– Regular exercise.

– Deep, mindful breathing.

– Meditation and mindfulness to remain grounded.

– Keeping a diary or journal to reflect on thoughts and feelings.

– Repeating affirmations to help control negative thoughts.

– Building a support network of friends and family to talk to.

– Getting plenty of sleep.

– Avoiding alcohol and too much caffeine.

– Prioritising themselves and making time to relax.


Diarrhoea can also be caused by many medicines, such as antibiotics, antidepressants and antacids which contain magnesium. Even constipation medicines can cause diarrhoea if used excessively.[6]

Top tips to treat diarrhoea:

1.) Hydrate! Drink plenty of water or squash to help replace the fluids you are losing through diarrhoea and to help combat dehydration. Adults should try to drink at least 200ml of liquid after each diarrhoea bowel movement. (Your urine should be clear or a pale straw colour.)[7]

2.) Take rehydration medicines, such as Dioralyte or Electrolade, to help rehydrate your body. They contain sugar, salt and water which helps to replace those which are lost from the body through diarrhoea.[8]

3.) Take anti-diarrhoea medication which contains loperamide, such as Imodium. If you are suffering from diarrhoea caused by bacteria a medicine which contains bismuth subsalicylate, such as Pepto-Bismol, may be beneficial.[9]

4.) If you suffer from IBS avoid eating too much high FODMAP food, but if you experience an IBS flare-up of diarrhoea then drink plenty of fluids and try to eat only low FODMAP foods until the bout of IBS passes.

5.) If you are experiencing cramping take the appropriate dose of paracetamol.

5.) Diarrhoea can be quite exhausting, so rest up with a hot water bottle on your abdomen until you feel better.

6.) Eat small meals composed of easily digestible foods, such as eggs, oats, crackers or soup.

7.) Avoid food which is high fat or high fibre until your diarrhoea has settled down.

When to see your doctor:

– If your symptoms persist for more than seven days.

– If you have a fever

– If there is blood in your stool.

– If you have a fever and have returned from being abroad.

– If you keep vomiting and cannot keep fluids down.

– If your diarrhoea is accompanied by severe, constant stomach cramping which does not improve.

[1] https://www.netdoctor.co.uk/conditions/digestive-health/a4912/diarrhoea/. Accessed 30.03.21.

[2] https://www.theibsnetwork.org/diarrhoea/. Accessed 30.03.21.

[3] https://www.netdoctor.co.uk/conditions/digestive-health/a4912/diarrhoea/. Accessed 30.03.21.

[4] https://www.monashfodmap.com/ibs-central/what-is-ibs/. Accessed 30.03.21.

[5] https://alittlebityummy.com/what-is-sorbitol-is-it-low-fodmap/#:~:text=When%20sorbitol%20is%20poorly%20absorbed,bowel%20movements%20(1%202). Accessed 30.03.21.

[6] https://www.netdoctor.co.uk/conditions/digestive-health/a4912/diarrhoea/. Accessed 30.03.21.

[7] https://www.netdoctor.co.uk/healthy-living/wellbeing/a27414/symptoms-of-dehydration/. Accessed 30.03.21.

[8] https://www.netdoctor.co.uk/medicines/digestion/a6583/dioralyte-rehydration-salts/. Accessed 30.03.21.

[9] https://www.netdoctor.co.uk/conditions/digestive-health/a4912/diarrhoea/. Accessed 30.03.21.

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