• Acute Disease;
  • Cholera [complications];
  • Dehydration [etiology; *therapy];
  • Diarrhea [complications; *therapy];
  • Fluid Therapy [*methods];
  • Polymers [therapeutic use];
  • Randomized Controlled Trials as Topic;
  • Rehydration Solutions [chemistry; *therapeutic use];
  • Adult;
  • Child;
  • Humans;
  • Infant



Acute diarrhoea is one of the principal causes of morbidity and mortality among children in low-income countries. Glucose-based ORS helps replace fluid and prevent further dehydration from acute diarrhoea. Since 2004, the World Health Organization has recommended the osmolarity < 270 mOsm/L (ORS ≤ 270 ) over the > 310 mOsm/L formulation (ORS ≥ 310). Glucose polymer-based ORS (eg prepared using rice or wheat) slowly releases glucose and may be superior.


To compare polymer-based ORS with glucose-based ORS for treating acute watery diarrhoea.

Search strategy

In September 2008, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2008, Issue 3), MEDLINE, EMBASE, LILACS, and mRCT. We also contacted researchers, organizations, and pharmaceutical companies, and searched reference lists.

Selection criteria

Randomized controlled trials of people with acute watery diarrhoea (cholera and non-cholera associated) comparing polymer-based and glucose-based ORS (with identical electrolyte contents).

Data collection and analysis

Two authors independently assessed the search results and risk of bias, and extracted data. In multiple treatment arms with two or more treatment groups, we combined outcomes as appropriate and compared collectively with the control group.

Main results

Thirty-four trials involving 4214 participants met the inclusion criteria: 27 in children, five in adults and two in both. Twelve trials used adequate methods to conceal allocation. Most compared polymer-based ORS with ORS ≥ 310. There were fewer unscheduled intravenous infusions in the polymer-based ORS group compared with glucose-based ORS (ORS ≥ 310 and ≤ 270 groups combined) (RR 0.75, 95% CI 0.59 to 0.95; 2235 participants, 19 trials). Adults positive for Vibrio cholerae had a shorter duration of diarrhoea with polymer-based ORS than with ORS ≤ 270 (MD -7.11 hours, SD -11.91 to -2.32; 228 participants, 4 trials). Wheat-based ORS resulted in lower total stool output in the first 24 hours compared with ORS ≤ 270 (MD -119.85 g/kg, SD -114.73 to -124.97; 129 participants, 2 trials). Adverse effects were similar for polymer-based ORS and glucose-based ORS.

Authors' conclusions

Polymer-based ORS shows some advantages compared to ORS ≥ 310 for treating all-cause diarrhoea, and in diarrhoea caused by cholera. Comparisons favoured the polymer-based ORS over ORS ≤ 270, but the analysis was underpowered. If specialists consider a potential role for polymer-based ORS, further trials against the current standard (ORS ≤ 270) will be required.

Plain Language Summary

Polymer-based oral rehydration solution (ORS) ORS for acute diarrhoea

Acute diarrhoea is a common cause of death and illness in developing countries. Oral rehydration solutions (ORS) have had a massive impact worldwide in reducing the number of deaths related to diarrhoea.

Most ORS is in the form of a sugar–salt solution, but over the years people have tried adding a variety of compounds ('glucose polymers') such as whole rice, wheat, sorghum, and maize. The aim is to slowly release glucose into the gut and improve the absorption of the water and salt in the solution. This review updates and expands on a 1998 Cochrane Review of rice-based ORS, and assesses the available evidence on the use of polymer-based ORS (both rice and non-rice based) in comparison with the glucose-based ORS.

The original ORS was based on glucose and had an osmolarity of ≥ 310 mOsm/L (ORS ≥ 310). Glucose-based ORS with a lower osmolarity was later introduced in attempts to improve efficacy, and is considered better at reducing the amount and duration of diarrhoea.

Thirty-four trials involving 4214 participants met the inclusion criteria: 27 in children; five in adults; and two in both. Most trials compared polymer-based ORS with a sugar–salt ORS with a particular strength (ORS ≥ 310), which is slightly more salty than the currently agreed best formula (≤ 270 mOsm/L). The trials' methodological quality was variable.

Fewer people in the polymer-based ORS group needed a drip to be rehydrated compared with those in the glucose-based ORS group. Adverse events were similar for polymer-based ORS and glucose-based ORS.

The authors conclude that polymer-based ORS show some advantages compared to glucose-based ORS for treating diarrhoea of any cause and in diarrhoea caused by cholera. Limited evidence favoured the polymer-based ORS over ORS ≤ 270. 

Further trials should compare the efficiency of ORS ≤ 270 with a polymer-based ORS.