Acute diarrhoea

– Acute diarrhoea is defined as at least 3 liquid stools per day for less than 2 weeks.
– There are 2 clinical types of acute diarrhoea:
• Diarrhoea without blood, caused by viruses in 60% of cases (rotavirus, enterovirus), bacteria (Vibrio cholerae, enterotoxigenic Escherichia coli, non Typhi SalmonellaYersinia enterocolitica) or parasites (giardiasis). Diseases, such as malaria, acute otitis media, respiratory tract infections, etc. can be accompanied by this type of diarrhoea.
• Diarrhoea with blood, caused by bacteria (Shigella in 50% of cases, Campylobacter jejuni, enteroinvasive or enterohaemorrhagic Escherichia coliSalmonella) or parasites (intestinal amoebiasis).
– Infectious diarrhoeas are transmitted by direct (dirty hands) or indirect (ingestion of contaminated water or food) contact.
– The high mortality rate from diarrhoeal diseases, even benign, is due to acute dehydration and malnutrition. This can be prevented by adequate rehydration and nutrition.

Clinical features

– First assess for signs of dehydration (Appendix 2a).
– Then look for other signs:
• profuse watery diarrhoea (cholera, enterotoxigenic E. coli),
• repeated vomiting (cholera),
• fever (salmonellosis, viral diarrhoea),
• presence of red blood in stools: see also Shigellosis and Amoebiasis.
– In a patient over 5 years with severe and rapid onset of dehydration, suspect cholera.


General principles:
– Prevent or treat dehydration: rehydration consists of prompt replacement of fluid and electrolyte losses as required, until the diarrhoea stops.
– Administer zinc sulfate to children under 5 years.
– Prevent malnutrition.
– Do not systematically administer antimicrobials: only certain diarrhoeas require antibiotics (see Antimicrobial treatment).
– Do not administer anti-diarrhoeal drugs or antiemetics.
– Treat the underlying condition if any (malaria, otitis, respiratory infection, etc.).

Prevention of dehydration 

Administer oral rehydration solution (ORS) according to the WHO Treatment Plan A to prevent dehydration (Appendix 2b).

Treatment of dehydration

Some ('moderate') dehydration 

Administer ORS according to the WHO Treatment Plan B to treat some dehydration (Appendix 2c)

Severe dehydration 

Ringer lactate (RL)
Children under 5 years: 20 ml/kg of RL over 15 minutes (to be repeated 2 times if necessary) then 70 ml/kg of RL over 3 hours
Children 5 years and over and adults: 30 ml/kg of RL over 30 minutes (to be repeated once if necessary) then 70 ml/kg of RL over 3 hours

Administer ORS as soon as possible in patients on IV fluids:
After each stool: 50 to 100 ml of ORS in children under 2 years; 100 to 200 ml of ORS in children aged 2 to 10 years; 200 to 250 ml of ORS in children over 10 years and adults.

Note: in severely malnourished children the IV rehydration rate is different (see Severe acute malnutrition, Chapter 1).

Prevention of malnutrition

Continue unrestricted normal diet. In breastfed children, increase the frequency of feeds. Breast milk does not replace ORS. ORS should be given between feeds.

Zinc supplementation

Zinc sulfate is given in combination with oral rehydration solution in order to reduce the duration and severity of diarrhoea, as well as to prevent further occurrences in the 2 to 3 months after treatment:
zinc sulfate PO
Children under 6 months: 10 mg (½ tablet) once daily for 10 days
Children from 6 months to 5 years: 20 mg (1 tablet) once daily for 10 days

Place the half-tablet or full tablet in a teaspoon, add a bit of water to dissolve it, and give the entire spoonful to the child.

Antimicrobial treatment

Diarrhoea without blood

Most acute diarrhoeas are caused by viruses unresponsive to antimicrobials. Antimicrobials can be beneficial in the event of cholera or giardiasis.
– Cholera: the most important part of treatment is rehydration. In the absence of resistance (perform antibiotic-sensitivity testing at the beginning of an outbreak), antibiotic treatment shortens the duration of diarrhoea. See the guide Management of a cholera epidemic, MSF.
– Giardiasis: see Intestinal protozoan infections, Chapter 6.

Diarrhoea with blood

– Shigellosis is the most frequent cause of bloody diarrhoea (amoebiasis is much less common). If there is no laboratory diagnosis to confirm the presence of amoebae, first line treatment is for shigellosis.
– Amoebiasis: antiparasitic treatment only if motile Entamoeba histolytica amoebae are found in stools or if a correct shigellosis treatment has been ineffective (see Amoebiasis).


– Breastfeeding reduces infant morbidity and mortality from diarrhoea and the severity of diarrhoea episodes.
– When the child is weaned preparation and storage of food are associated with the risk of contamination by faecal micro-organisms: discourage bottle-feeding; food must be cooked well; milk or porridge must never be stored at room temperature.
– Access to sufficient amounts of clean water and personal hygiene (washing hands with soap and water before food preparation and before eating, after defecation etc.) are effective methods of reducing the spread of diarrhoea.
– In countries with a high rotavirus diarrhoea fatality rate, the WHO recommends routine rotavirus vaccination in children between 6 weeks and 24 months of age.1


  1. Weekly epidemiological record/Relevé épidémiologique hebdomadaire 1st February 2013, 88th year/1er Février 2013, 88e année No. 5, 2013, 88, 49–64. [Accessed 02 January 2019]