INTRODUCTION The discovery of oral rehydration salts (ORS) solution for the treatment of dehydration due to diarrhoea is considered to be one of the greatest achievements of medical research in the 20th century (1). Since it was recommended by the World Health Organization (WHO) in 1978 for the management of all types of diarrhoea in all age-groups, numerous studies have been undertaken to develop an 'improved' ORS. The goal was to discover a product that would be at least as safe and effective as standard ORS solution for preventing or treating dehydration from all types of diarrhoea but which, in addition, would reduce stool output or have other important clinical benefits. One approach has emphasized reducing the osmolarity of ORS solution to avoid possible adverse effects of hypertonicity on net fluid absorption. This was done by reducing glucose and salt (NaCl) concentrations in the solution (2-10). Results of studies conducted on children with non-cholera diarrhoea and comparison of this reduced-osmolarity ORS solution with the standard WHO-ORS solution showed that reduced-osmolarity ORS solution significantly reduced stool output, vomiting, and the need for unscheduled intravenous infusion (7). Besides, reduced-osmolarity ORS solution also significantly decreased mean serum sodium concentration at 24 hours. However, all cases of hyponatraemia reported in these studies were asymptomatic. Based on these results, it appears that reduced-osmolarity ORS solution, containing a reduced amount of sodium and glucose, had beneficial effects on the clinical course of diarrhoea and is as safe as the standard WHO-ORS solution for use in acute infantile diarrhoea (7).