Reduced osmolarity oral rehydration solution for treating dehydration caused by acute diarrhoea in children

Children with diarrhoea lose body water and sometimes become dehydrated. A solution of sugar and salt dissolved in water is widely used to treat dehydration caused by diarrhoea. This reviews shows that a solution of lower osmolarity than the current international standard means fewer children subsequently require an intravenous drip.

Authors' conclusions: 

In children admitted to hospital with diarrhoea, reduced osmolarity ORS when compared to WHO standard ORS is associated with fewer unscheduled intravenous fluid infusions, lower stool volume post randomization, and less vomiting. No additional risk of developing hyponatraemia when compared with WHO standard ORS was detected.

Read the full abstract...

Oral rehydration solution (ORS) has reduced childhood deaths from diarrhoea in many countries. Recent studies suggest that the currently recommended formulation of ORS recommended by the World Health Organization (WHO) may not be optimal, and solutions that contain lower concentrations of sodium and glucose may be more effective.


To compare reduced osmolarity ORS with WHO standard ORS in children with acute diarrhoea.

Search strategy: 

CENTRAL (The Cochrane Library, Issue 3, 2004), MEDLINE (1966 to July 2004), EMBASE (1988 to July 2004), and Current Contents (July 2004) were searched. Additional trials were identified by hand searching. Content experts were contacted.

Selection criteria: 

Randomized controlled trials comparing reduced osmolarity ORS with the WHO standard ORS formulation. The primary outcome was unscheduled intravenous fluid infusion. Secondary outcomes were measures of clinical illness.

Data collection and analysis: 

Two reviewers extracted data. We tested for heterogeneity using the Chi-square statistic, conducted sensitivity analysis by allocation concealment, and the regression approach to assess funnel plot asymmetry from selective trial publication.

Main results: 

The primary outcome, unscheduled intravenous fluid infusion, was reported in 11 trials. In a meta-analysis of 8 trials, reduced osmolarity ORS was associated with fewer unscheduled intravenous fluid infusions compared with WHO standard ORS (Mantel Haenzel odds ratio 0.59, 95% confidence interval 0.45 to 0.79) with no evidence for heterogeneity between trials. No unscheduled intravenous fluid infusion therapy was required in any participant in three trials.

Eleven trials reported stool output, and data suggested less stool output in the reduced osmolarity ORS group. Vomiting was less frequent in the reduced osmolarity group in the six trials reporting this. Six trials sought hyponatraemia, with events in three studies, but no obvious difference between the two arms.